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4DOS Version 3.03
A PC-DOS / MS-DOS Command Processor
Distributed by:
JP Software, Inc.
P.O. Box 1470
E. Arlington, MA 02174, USA
(617) 646-3975
_______
____|__ | (tm)
--| | |-------------------
| ____|__ | Association of
| | |_| Shareware
|__| o | Professionals
-----| | |---------------------
|___|___| MEMBER
Written by Rex C. Conn and Tom Rawson
JP Software, Inc.
P.O. Box 1470
E. Arlington, MA 02174, USA
(617) 646-3975 voice
(617) 646-0904 fax
(800) 368-8777 orders only
Electronic mail to:
CompuServe 75300,210
BIX "trawson"
InterNet, Bitnet, etc.: 75300.210@compuserve.com
Program and Documentation Copyright 1988 - 1991, Rex C. Conn and
JP Software, Inc. All rights reserved.
Portions Copyright 1987, 1988, 1990 Microsoft Corporation
Portions Copyright 1987, 1989 Borland International
Portions Copyright 1987, 1988, 1989 TurboPower Software
4DOS is a registered trademark of JP Software Inc.
PC-DOS, PC, PC XT, PC AT, and PS/2 are trademarks of IBM Corporation.
MS-DOS, OS/2, and Windows are trademarks of Microsoft Corporation.
1-2-3 is a trademark of Lotus Development Corporation.
dBASE is a trademark of Ashton Tate.
386-To-The-Max and Move-Em are trademarks of Qualitas Inc.
DESQview and QEMM are trademarks of Quarterdeck Office Systems
Brief is a trademark of UnderWare Inc.
4DOS Reference Manual Copyright 1991, JP Software Inc.
ACKNOWLEDGEMENTS
We couldn't produce a product like 4DOS without the dedication and
quality work of many people. Our thanks to all these folks:
JP Software staff: Mike Bessy, Helen Coyne, Hayyim Feldman,
Henry Harvey, Susan Mampre, Ellen Stone.
Beta testers: Bruce Aldrich, Mike Bessy, David Birnbaum, Jeff
Bishop, "Dr. File Finder" (Mike Callahan), Gary Clanfield, John
Cooper, Chris DeVoney, Emanuel Donchin, Stan Dvoskin, John
Fleming, Doug Frank, Peter Frank, Gary Gibson, Tim Grissom, Ken
Harwell, Keith Hawes, Bob Huntley, John James, Tom Kellen, Bob
Kertesz, Dave Lemire, Kevin Lockwood, Brad McDonald, John McKown,
Burt Model, Stuart Moore, Phil Newman, Jorge Ochoa-Lions, Shakib
Otaqui, John Peterson, Ed Phillips, Mike Phillips, Sam Pierce,
Chip Rabinowitz, Dan Rawson, David Rodman, Chris Rousseau, Alan
Samuels, Guy Scharf, Martin Schiff, Bill Shaffer, Malcolm Shealy,
Stephen Spehn, Michael Stein, Ted Thompson, Brian Trainer, Thomas
Traubitz, Randy Wallin, Bill Walton, Iram Weinstein, Joe Zott,
and anyone else we forgot!
Beta test support: David Moskowitz, Guy Scharf, and all the
sysops of the CompuServe CONSULT forum.
BBS support: Channel 1 sysops Brian Miller and Tess Heder.
The 4DOS 3.0 HELP system was originally written by Ross Neilson
Wentworth, and is now owned and distributed by JP Software.
The following tools are used in creating and maintaining 4DOS:
Compilers: Microsoft C 6.0 and Macro Assembler 5.1
Turbo Pascal 5.5 (Borland)
Libraries: Turbo Professional 5.0 (TurboPower Software)
Editors: Edix (Emerging Technology), Brief (Solution
Systems)
Debuggers: Periscope (The Periscope Company), Soft-ICE
(Nu-Mega Technologies)
Version Control: PVCS (Polytron)
The following suppliers produce the finished product:
Manual Printing: Causeway Print, Boston
Disk Duplication: Diversified Systems Group, Issaquah, WA
4DOS Reference Manual Copyright 1991, JP Software Inc.
TABLE OF CONTENTS
Introduction i
Registration Information ii
4DOS License Agreement iii
Technical Support vi
4DOS Features 1
Installation 9
4DOS Files 10
Test Driving 4DOS 11
Quick Start 12
Automatic Installation 13
DOS Shells Explained 14
COMSPEC 15
Manual Installation 16
Memory Usage 18
Setting up CONFIG.SYS 19
Startup Options 21
4DSHELL 25
AUTOEXEC and 4START 25
4DOS and COMMAND.COM 26
Using 4DOS 27
Starting 4DOS 27
Command Line Editing 28
Command History and Recall 29
Multiple Commands 30
Conditional Commands 30
Escape Character 31
Command Echoing 32
Argument Quoting 32
Batch Files 33
Aliases 35
Executable Extensions 37
Keystack 39
Environment Variables 40
Variable Functions 42
I/O Redirection 43
Command Parsing 45
4DOS Reference Manual Copyright 1991, JP Software Inc.
Command Reference Guide 46
? 48
ALIAS 49
ATTRIB 52
BEEP 53
BREAK 54
CALL 55
CANCEL 56
CD / CHDIR 57
CDD 58
CHCP 59
CLS 60
COLOR 61
COPY 62
CTTY 64
DATE 65
DEL / ERASE 66
DELAY 67
DESCRIBE 68
DIR 69
DIRS 72
DRAWBOX 73
DRAWHLINE 74
DRAWVLINE 75
ECHO 76
ENDLOCAL 77
ESET 78
EXCEPT 79
EXIT 80
FOR 81
FREE 82
GLOBAL 83
GOSUB 84
GOTO 85
HELP 86
HISTORY 87
IF 88
IFF 91
INKEY 92
INPUT 93
KEYSTACK 94
LIST 95
LOG 97
MD / MKDIR 98
MEMORY 99
MOVE 100
PATH 102
PAUSE 103
POPD 104
PROMPT 105
PUSHD 107
4DOS Reference Manual Copyright 1991, JP Software Inc.
QUIT 108
RD / RMDIR 109
REM 110
REN / RENAME 111
RETURN 112
SCREEN 113
SCRPUT 114
SELECT 115
SET 117
SETDOS 119
SETLOCAL 122
SHIFT 123
SWAPPING 124
TEE 125
TEXT 126
TIME 127
TIMER 128
TYPE 129
UNALIAS 130
UNSET 131
VER 132
VERIFY 133
VOL 134
Y 135
Appendix A - Error messages 136
Appendix B - ASP 146
Appendix C - Key codes 148
Appendix D- Programming 149
Appendix E - Tips and
Troubleshooting 150
Glossary 162
Index 173
4DOS Reference Manual Copyright 1991, JP Software Inc.
Introduction
Welcome, and thanks for trying 4DOS!
4DOS is designed to help you get the most out of your IBM PC or
compatible system. It replaces COMMAND.COM, the command
interpreter that comes with all versions of MS-DOS and PC-DOS.
You'll find 4DOS provides a wide variety of capabilities
COMMAND.COM can't, ranging from a vastly enhanced DIR command, to
point-and-shoot file selection for any command, to the ability to
completely redefine your system's commands. Yet 4DOS is fully
compatible with COMMAND.COM.
4DOS is a "DOS shell" (a program that gives you access to DOS
functions and commands), but it's unlike most DOS shells on the
market. Virtually all of these shells are designed to isolate
the novice user from the DOS command line. 4DOS, on the other
hand, is intended to make DOS easier to use and to make you more
productive while working at the command line. It provides
enhancements to most of the DOS commands, as well as more than 40
new commands. These improvements make 4DOS a much richer and
more powerful working environment than COMMAND.COM, without
sacrificing the compatibility, flexibility and control you get
from working at the command line. If you're tired of the
limitations of COMMAND.COM, you'll love 4DOS!
4DOS is distributed as shareware, which means if you've
downloaded it from a bulletin board or obtained it from a friend,
you can try it out before you decide whether you'd like to keep
it. Like all shareware, if you do decide to keep 4DOS, you must
pay a registration fee.
4DOS is also distributed through normal retail channels. If you
purchased a retail copy of 4DOS, it includes a shareware disk
which you can share with your friends and associates.
The following pages include information on registration, the 4DOS
license agreement, and technical support for 4DOS.
The text in this ASCII manual is essentially the same as that in
the printed manual. Changes from the original version 3.0 manual
have been made to correct typographical errors or document small
changes in the software, but a few significant new features which
would require repagination of the text are not included. For
complete documentation on changes in versions 3.01 through 3.03
see the file UPDATE30.DOC.
4DOS Reference Manual Copyright 1991, JP Software Inc. i
Registration Information
4DOS is a copyrighted program protected by both U.S. and
international copyright law. If you obtained 4DOS from a
shareware disk vendor, an on-line computer service or bulletin
board, a friend or colleague, or another similar source, you have
an unregistered (trial) copy. You are authorized to use this
copy without charge for a limited period of time under the terms
of the 4DOS license agreement. After this time is up, you must
register and pay for 4DOS to continue using it.
This method of distribution is known as shareware. It allows you
to determine whether 4DOS meets your needs before you pay for it.
The registration fee for a single copy of 4DOS is $50. Payment
of this fee entitles you to:
∙ A disk with the latest version of 4DOS, registered to you,
and a copy of the typeset-quality printed and bound 4DOS
manual.
∙ An upgrade to the next major release of 4DOS.
(There is no charge from JP Software for downloading an
upgrade or maintenance release. For an upgrade on diskette
there will be a minimal charge to cover our cost in
sending it to you.)
∙ Technical support via electronic mail or telephone.
∙ A subscription to the 4DOS newsletter.
If you prefer, you may register for $35 and receive only the disk
and notices of future upgrades. Multi-system licenses are also
available; contact JP Software for more information.
If you purchased a complete copy of 4DOS with printed manual from
a software dealer, your copy came with a yellow registration
card. Return this card promptly to JP Software to ensure you
are registered with us, and to receive technical support and
notices of future upgrades. If you purchased 4DOS directly from
JP Software and paid the full $35 or $50 fee, you are already
registered, and no registration card is necessary.
4DOS Reference Manual Copyright 1991, JP Software Inc. ii
4DOS License Agreement
(1) Copyright: The 4DOS program and all other programs and
documentation distributed or shipped with it are Copyright 1988 -
1991, Rex C. Conn and JP Software Inc., or are distributed
under license to JP Software Inc., and are protected by U.S. and
international copyright law. In the rest of this document, this
collection of programs is referred to simply as "4DOS". You are
granted a license to use your copy of 4DOS only under the terms
and conditions specified in this license agreement.
(2) Definitions: 4DOS is distributed in two forms. A
"registered" copy of 4DOS is a copy distributed on diskette,
purchased from JP Software or from a dealer, and which includes
a serial number and the legend "licensed" or "registered" in the
program sign-on message and on the diskette label. A "shareware"
copy of 4DOS is a copy distributed on diskette or via an
electronic bulletin board, on-line service, or other electronic
means, obtained from a shareware disk vendor, or obtained from
another individual, and which displays the legend "shareware" in
the program sign-on message, and in most cases on the diskette
label as well (if applicable). Throughout this document the term
"JP Software" refers to JP Software Inc., a Massachusetts
corporation.
(3) Shareware Copies: Shareware copies of 4DOS are distributed
to allow you to try the program before you pay for it. They are
Copyright 1988 - 1991, Rex C. Conn and JP Software Inc., and do
not constitute "free" or "public domain" software. You may use a
shareware copy of 4DOS at no charge for a trial period of up to
21 days. If you wish to continue using 4DOS after that period,
you must purchase a registered copy. If you choose not to
purchase a registered copy, you must stop using 4DOS, though you
may keep copies and pass them along to others.
(4) Registered Copies: Registered copies of 4DOS are
distributed to those who have purchased them. Your registered
copy of 4DOS may only be used on the number of computers
specified on the diskette label and program sign-on screen.
(5) Use of One Copy on Two Computers: If you have a registered
copy of 4DOS which is licensed for use on a single computer, you
may install it on two computers used at two different locations
(for example, at work and at home), provided there is no
possibility that the two computers will be in use at the same
time, and provided that you yourself have purchased 4DOS, or if
4DOS was purchased by your employer, that you have your
employer's explicit permission to install 4DOS on two systems as
described in this paragraph. The right to install one copy of
4DOS on two computers is limited to copies originally licensed
for use on a single computer, and may not be used to expand the
number of systems covered under a multi-system license.
4DOS Reference Manual Copyright 1991, JP Software Inc. iii
(6) Use of 4DOS on Networks or Multiple Systems: You may
install your registered copy of 4DOS on a computer attached to a
network, or remove it from one computer and install it on a
different one, provided there is no possibility that your copy
will be used by more users than it is licensed for. A "user" is
defined as one keyboard which is connected to a computer on which
4DOS is installed, regardless of whether or not the user of the
keyboard is aware of the installation or use of 4DOS in the
system.
(7) Making Copies: You may copy any version of 4DOS for normal
backup purposes, and you may give copies of the shareware version
to other individuals, which they may also use and copy subject to
the terms of this agreement. If you copy the shareware version
of 4DOS for others, you must include all of the files distributed
with it, including this one. You may not give copies of the
registered version to any other person for any purpose, and you
may not make any copies of the printed and bound 4DOS manual
without explicit written permission from JP Software.
(8) Distribution Restrictions: You may NOT distribute 4DOS other
than through individual copies of the shareware version passed to
friends and associates for their individual use. Specifically,
you may not place 4DOS or any part of the 4DOS package in any
user group or commercial library, or distribute it with any other
product or as an incentive to purchase any other product, without
express written permission from JP Software, and you may not
distribute for a fee, or in any way sell copies of 4DOS or any
part of the 4DOS package. However if you are a shareware disk
vendor approved by the Association of Shareware Professionals (ASP),
or a non-profit, tax-exempt user group, you may place 4DOS in your
library without prior written permission, provided you notify JP
Software within 15 days of doing so; and for shareware disk vendors,
provided your application has been fully approved in writing by the
ASP, and is not simply submitted or awaiting review.
(9) Use of 4DOS: 4DOS is a powerful program. While we have
attempted to build in reasonable safeguards, if you do not use
4DOS properly you may destroy files or cause other damage to your
computer software and data. You assume full responsibility for
the selection and use of 4DOS to achieve your intended results.
As stated below, JP Software limits its warranty to replacement
of a defective program diskette or manual.
(10) LIMITED WARRANTY: JP Software warrants to owners of
registered copies of 4DOS that the software will operate in
accordance with the description given in the documentation, and
that the diskette and manual will be free of physical defects
which interfere with normal use. BOOT.SYS and the software on
the 4DOS Utility Disk which was not created by JP Software,
as stated in the documentation provided on the disk, is not
warranted to operate in accordance with its documentation, and
is sold AS-IS AND WITHOUT WARRANTY OF ANY KIND BY JP SOFTWARE.
For a period of 90 days from the date of your purchase of 4DOS,
4DOS Reference Manual Copyright 1991, JP Software Inc. iv
JP Software will, at its sole option and subject to the restrictions
above and below, repair or replace any defective item(s), or refund
the purchase price of any diskette and/or manual and/or any other
parts or components of 4DOS found to be defective, if such defect
is the fault of JP Software and not the result of misuse or
abuse. Such a refund, repair, or replacement shall be your sole
remedy for any defects, program error(s), or documentation
error(s). In no event shall JP Software be responsible for any
other costs or damages whatsoever due to errors in usage or your
failure to read, understand, or follow instructions in the
documentation. JP SOFTWARE MAKES NO OTHER WARRANTIES, EXPRESS
OR IMPLIED, INCLUDING WITHOUT LIMITATION THE WARRANTIES OF
MERCHANTABILITY AND OF FITNESS FOR A PARTICULAR PURPOSE. JP
Software's warranty is expressly limited to the cost of
replacement of any defective diskette or other part.
(11) Satisfaction Guarantee: If you are dissatisfied with a
registered copy of 4DOS for any reason (whether or not you find a
software error or defect), you may return the entire package at
any time up to 90 days after purchase for a full refund of your
original registration fee.
4DOS Reference Manual Copyright 1991, JP Software Inc. v
Technical Support
Technical support for 4DOS is available to registered users. If
you are not a registered user, we will provide you with
assistance to install a shareware copy of 4DOS and evaluate it
during the 21 day evaluation period, but we cannot provide
continuing support beyond that until you purchase 4DOS.
The best way to contact us for support is by modem, in one of the
following public 4DOS support conferences. The numbers in
parentheses indicate the usual delay, in days, to receive a reply
to a message.
CompuServe / PCMagNet: Primary support is via the JP Software
section of the CompuServe PCVENB forum (GO PCVENB) (1 day). We
also monitor the CompuServe CONSULT and IBMSYS forums, and the
PCMagNet UTILFORUM (2-5 days).
Bulletin Boards: Primary support is via the 4DOS conferences on
the Channel 1 BBS, Boston, MA, 617-354-8873 (1-3 days). Additional
support is available from many local BBSes via the 4DOS conferences
on the InterLink, PC Relay, FidoNet, and SmartNet BBS Networks (3-5
days). Please note that Channel 1 is an independent bulletin board
which has agreed to serve as a home base for 4DOS support, but is
not owned or operated by JP Software.
BIX: Support is available via the ibm.dos conference, topic 4DOS
(3-5 days).
In addition, you can contact JP Software for support by mail,
telephone, fax, or electronic mail. Addresses and phone numbers
are listed on the first page of this manual.
We prefer support via one of the electronic services listed
above, or via electronic mail, as it allows correspondence at
convenient times regardless of time zones and work schedules, and
it provides a record of the communication. However, telephone
and fax support are also provided to those users who do not have a
modem or who need an quick response.
4DOS Reference Manual Copyright 1991, JP Software Inc. vi
4DOS Features
4DOS is a complete replacement for COMMAND.COM, the command
processor provided with MS-DOS or PC-DOS. (References in this
manual to MS-DOS also apply to PC-DOS.) 4DOS is compatible with
MS-DOS versions 2.0 to 4, and the OS/2 DOS compatibility box, and
adds many enhancements to your MS-DOS prompt, including:
Minimal Memory Usage
4DOS requires less than 4K of your precious RAM for its
resident portion (less than 1K with XMS swapping!), and can
use EMS, XMS, or disk for swapping its transient portion.
Fast Batch Files
4DOS 3.0 adds a new batch file extension (.BTM, "batch to
memory") that is compatible with 99% of your existing batch
files, but runs several times faster.
Executable Extensions
In addition to the normal executable file extensions (.COM,
.EXE, .BAT, and .BTM), 4DOS allows you to define additional
extensions and the programs they should invoke. For
example, entering a document name could automatically invoke
your word processor.
On-line Help
4DOS provides help for all of its internal commands, as well
as the MS-DOS external commands. You can get help by
pressing the F1 key at the command prompt. The 4DOS help
facility is extensible, so you can add help for your own
programs. (Modifications to the help facility require the
4DOS utility disk, which contains the source text and help
file compiler.)
Command Line Editing
4DOS provides command line editing, including insert and
delete, and full cursor key support. 4DOS also offers
interactive expansion of wildcard filenames on the command
line.
4DOS Reference Manual Copyright 1991, JP Software Inc. 1
Command History
4DOS lets you view, search, modify, and reexecute your
previous commands. The commands are saved in memory, and
can be recalled with the cursor keys. The command history
list size is user-defined, from 512 to 8192 characters.
Flexible File Wildcards
4DOS offers more flexible wildcards than COMMAND.COM. For
example, you can display all the files that have a "2"
anywhere in their filename by entering:
dir *2*.*
File Descriptions
4DOS allows you to provide descriptions (up to 40
characters) for each of your files and directories. The
descriptions are displayed with the filenames when you use
the DIR or SELECT commands. The description goes with a
file when you COPY, ERASE, MOVE, or RENAME it.
Multiple Commands on a Single Line
You can enter several commands on a line by separating them
with a ^ (caret), or other user-defined character.
Expanded and Editable Environment
4DOS provides a user-defined environment size from 512 to
32000 characters. You can interactively edit environment
entries with the ESET command.
Environment Variables
Environment variables allow you to associate a string of
characters with a variable name, substituting that string
when the name is used. 4DOS provides a number of predefined
variables, including system date and time, current
directory, and default disk, and "variable functions," for
returning substrings, the parts of a filename (path, name,
extension), etc.
4DOS Reference Manual Copyright 1991, JP Software Inc. 2
Aliases
Aliases allow you to rename or reconfigure commands (for
example, to pass default parameters to a command, or to give
MS-DOS the look and feel of a different operating system),
or to define a new command as a combination of several other
commands. Aliases support batch file-like arguments (%1,
%2, etc.) and environment variables, so when combined with
the multiple commands feature, they act as very fast batch
files.
Expanded Command Line
4DOS expands the MS-DOS command input line from 127 to 255
characters for internal commands. (Because MS-DOS truncates
the command line for external commands to 127 characters,
4DOS makes the full command line available to your programs
through the CMDLINE environment variable.)
Conditional Commands
4DOS includes two new command line operators: || (OR) and &&
(AND). They allow you to control the execution of
subsequent commands based on the result of the previous
command.
Additional Redirection Options
In addition to redirection of standard input and standard
output, 4DOS supports redirection of standard error, and the
option to prevent overwriting existing files. 4DOS also
provides TEE and Y "pipe fittings."
EGA/VGA Support
4DOS supports Monochrome, CGA, EGA and VGA displays with any
number of lines and columns per screen.
Networks
4DOS supports MS-DOS compatible networks, including 3Com 3+
and Novell Netware.
4DOS Reference Manual Copyright 1991, JP Software Inc. 3
New and Enhanced Commands
4DOS provides many new internal commands, and new options for
existing commands. Most 4DOS commands can take multiple
arguments. For example, you can delete several files with a
single DEL command:
del *.bak test.wks oldfile.txt
You can also copy several files with a single COPY command (the
target directory here is a:\):
copy *.wks memo.doc *.c a:\
The following list is intended to give you a sampling of some of
the new and enhanced commands. See the Command Reference Guide
for full details.
ALIAS / UNALIAS
Define aliases for commonly used commands, allowing you to
execute a complex series of commands with a few keystrokes.
ATTRIB
Display or change the file attributes (read-only, hidden,
system, and archive) for the specified files and/or
directories.
CDD
Change the default drive and directory.
COLOR
Set the screen foreground and background colors.
COPY
COPY includes new switches for copying only updated files
(where the source is newer than the target), and to prompt
for confirmation before overwriting existing files.
4DOS Reference Manual Copyright 1991, JP Software Inc. 4
DESCRIBE
Add 40-character descriptions to filenames. The
descriptions are displayed when using DIR and SELECT.
DIR
Display the disk directory with a wide variety of options,
including 1, 2, 4, or 5 column display; sorted by name,
extension, description, size, or date/time; display
subdirectories; display file attributes; and display
subtotals only.
ESET
Interactively edit environment variables and aliases.
EXCEPT
Execute a command except on the specified file(s).
FREE
Display the total and free disk space for the specified
drive(s).
GLOBAL
Execute a command in the current directory and all of its
subdirectories.
HELP
Display a pop-up help window for 4DOS internal commands and
MS-DOS external commands.
HISTORY
Display, clear or load the command history list.
LIST
Display a file on the screen. LIST provides forward and
backward paging, vertical and horizontal scrolling, text
search, and printing.
4DOS Reference Manual Copyright 1991, JP Software Inc. 5
LOG
Keep a disk log of each command executed, with the date and
time.
MEMORY
Display the amount of total and available DOS, expanded,
XMS, and extended memory, and environment space.
MOVE
Move files between directories and/or drives, and optionally
prompt before overwriting existing files.
PUSHD / POPD / DIRS
Use a "directory stack" to change directories, perform some
work, and then return to the original directory.
RENAME
In addition to renaming files, 4DOS also allows you to
rename files to another directory, and to rename
directories.
SELECT
Perform a command on selected files (using point-and-shoot
selection).
SETDOS
Configure the 4DOS internal parameters, including the
default line editing mode (insert or overstrike), the
default batch echo mode, the compound command character, the
escape character, screen size, and cursor shape.
TIMER
A system stopwatch for timing events, including split times.
4DOS Reference Manual Copyright 1991, JP Software Inc. 6
Enhanced Batch Processor
The batch processor in 4DOS is compatible with batch files
written for COMMAND.COM, and includes several new and enhanced
commands to make batch file programming easier and more powerful,
including:
BEEP
Beep the speaker at the specified frequency and for the
specified duration.
CALL
Execute nested batch files without loading a secondary
copy of the command processor.
CANCEL
Terminate nested batch file processing.
DELAY
Wait for the specified period of time before continuing
batch processing.
DRAWBOX / DRAWHLINE / DRAWVLINE
Draw boxes, horizontal, and vertical lines in single or
double widths, in your choice of colors. These commands
automatically make connectors when crossing other lines.
GOSUB / RETURN
Call subroutines within a batch file.
IF
Many new comparison tests, (including less than, greater
than, etc), and tests for memory, disk, and display type.
4DOS Reference Manual Copyright 1991, JP Software Inc. 7
IFF / THEN / ELSEIFF / ELSE / ENDIFF
Allows nested IF / THEN / ELSE tests in batch files and
aliases, and supports all of the new IF tests (see above).
INPUT / INKEY
Input variables from the keyboard while in a batch
file, with an optional timeout period.
KEYSTACK
Send keystrokes to a program, as if entered from the
keyboard.
QUIT
Exit the current batch file.
SCREEN
Position the cursor and (optionally) display text.
SCRPUT
Position the cursor and display text in the specified
colors.
SETLOCAL / ENDLOCAL
Define a local environment within a batch file, saving the
original environment, disk, and directory, and restoring
them when finished.
SHIFT
Optionally specify how many positions to shift,
including reverse SHIFTs.
TEXT / ENDTEXT
Display a block of text.
4DOS Reference Manual Copyright 1991, JP Software Inc. 8
Installation
4DOS is written for the IBM PC, PC/XT, PC/AT, PS/2 (all models),
and compatibles. It requires MS-DOS 2 or above (MS-DOS 3.1 or
above is recommended), and uses less than 4K of RAM in swapping
mode, or about 70K in resident mode.
If you are new to 4DOS, read through this section until you get
to "Automatic Installation." If you have a diskette copy of
4DOS, you can follow the automatic installation procedure, and
come back later to read the section on manual installation and
configuration.
If you would like to try out 4DOS before fully installing it, see
the section Test Driving 4DOS.
If you are an experienced 4DOS user, do not have 4DOS on
diskette, or prefer manual installation for any other reason,
read through this section before installing 4DOS. See the Quick
Start section for brief instructions for experienced users on how
to install 4DOS.
4DOS Files
The files listed below are part of 4DOS. Depending on where you
obtained your copy, you may find the files in a compressed form,
usually in a file with the extension .ZIP or .ARC. These files
may change from time to time. See the file README.DOC for up to
date information on which files are included with your copy of
4DOS.
INSTALL.BAT* The automatic installation batch file. Note that
INSTALL.BAT will only work with copies of 4DOS
distributed on diskette.
4DOS.COM The 4DOS shell loader and swapper.
4DOS88.EXE Replaces COMMAND.COM as the default MS-DOS command
processor on any PC compatible system.
4DOS286.EXE A version of 4DOS optimized for 80186, 80286,
80386, 80486, V20 and V30 processors. 4DOS286
is slightly smaller and faster than 4DOS88.
4DOS Reference Manual Copyright 1991, JP Software Inc. 9
4DOS.DOC The 4DOS manual.
KEYSTACK.SYS This device driver provides the support for the
4DOS KEYSTACK command.
HELP.EXE This is the on-line help program for 4DOS. It
provides help for all of the internal 4DOS
commands, and for the external MS-DOS commands.
DOS.HLP The text file for HELP.EXE.
ALIASES Sample predefined 4DOS aliases.
PKUNZIP.EXE* Program used to uncompress the .ZIP files.
PKUNZIP.DOC* Documentation for PKUNZIP.EXE.
COMPAT.DOC Compatibility notes -- look here if you have
trouble getting another program running with
4DOS.
README.DOC Last-minute revisions and bug reports.
* Included only with diskette copies of 4DOS.
Compatibility
Compatibility information varies from release to release of both
4DOS and other products. See Appendix E - Troubleshooting 4DOS
for general usage notes and troubleshooting tips. The file
COMPAT.DOC (distributed with 4DOS) contains the latest
compatibility information available to us, along with information
on how to address known compatibility problems.
If the information in Appendix E and COMPAT.DOC doesn't solve
your problem, contact JP Software directly for technical
support.
4DOS Reference Manual Copyright 1991, JP Software Inc. 10
Test Driving 4DOS
While 4DOS is normally installed as your system's primary command
processor, you can try it out by running it just like any other
program. This allows you to explore the features and advantages
of 4DOS before doing a full installation.
To try 4DOS, copy the files 4DOS.COM and 4DOS88.EXE to your
system disk. If the copy of 4DOS you received has these files
compressed, use the following command to decompress them (this
example assumes the files are stored in the compressed file
A:\4DOS30.ZIP, and you are decompressing them with the PKUNZIP
program onto the root directory of drive C)
pkunzip a:\4dos30 c:\4dos.com c:\4dos88.exe
You can put these files in any directory, including a separate
4DOS directory if you like. Change to that directory, and enter
the command:
4dos
You will see the 4DOS sign-on message and a prompt. You are now
ready to try 4DOS! You can return to COMMAND.COM at any time by
typing:
exit
Note that the 4DOS KEYSTACK command will be unavailable because
it requires the KEYSTACK.SYS device driver to be installed.
Installation of KEYSTACK.SYS is described in the Manual
Installation section.
The 4DOS HELP command will also be unavailable. To try it out,
decompress and/or copy the files HELP.EXE and DOS.HLP to a
directory included in your PATH statement. Then type HELP or
press F1 at the 4DOS prompt to access the 4DOS online help
facility.
There are a few situations where you will need to make some
changes in the method described above. If your system does not
have a hard disk, EMS, or XMS memory, use the following command
to start 4DOS:
4dos /s:n
This will disable 4DOS swapping (floppy disk swapping is too slow
to be useful). Under these conditions 4DOS will require about
70K of memory, instead of the under 4K required in swapping mode.
If you are running network software, you can start 4DOS as above,
but do so after your network is loaded. If you are running a
multitasking or task switching environment such as DESQview or
Microsoft Windows, load 4DOS as above within a partition or
4DOS Reference Manual Copyright 1991, JP Software Inc. 11
window, rather than attempting to load the operating environment
after 4DOS has started. (These restrictions apply only to
testing 4DOS. Once it is installed as the primary shell and
configured properly for your system, they will not be necessary.)
Quick Start
If you are an experienced MS-DOS user, the following instructions
will get you up and running with 4DOS. If you have trouble or if
these instructions don't make sense, use the automatic or manual
installation procedures described later in this section. These
instructions assume you are booting from a hard disk which is
drive C.
1) Be sure you have a bootable MS-DOS floppy.
2) Decompress and/or copy the files 4DOS.COM, KEYSTACK.SYS, and
4DOS286.EXE (for 8018x/286/386/486, V20, and V30 processors)
or 4DOS88.EXE (for 808x processors) to the root directory of
drive C:.
3) If you have a registered (non-shareware) copy of 4DOS,
change to the root directory of drive C and run the BRAND
program by entering "A:BRAND". Enter the serial number from
the diskette label, and your EXE file will be branded as a
fully registered copy. If you only copied one of the EXE
files, ignore the error message about the missing EXE file.
4) Decompress and/or copy the files HELP.EXE and DOS.HLP to a
directory included in your PATH statement.
5) Edit CONFIG.SYS so that it contains the following lines
(delete any existing SHELL= line):
device=c:\keystack.sys
shell=c:\4dos.com /E:n /A:m /P
where n is your desired environment size, and m is the
desired alias list size (in bytes). The default values are
/E:512 and /A:1024.
6) Reboot your system. The system will load 4DOS (swapping to
XMS, EMS, or disk, depending on what is available), execute
AUTOEXEC, and return to the 4DOS prompt when AUTOEXEC is
done.
7) If you are using PROMPT commands in AUTOEXEC to transmit
ANSI control sequences for key redefinitions, they will not
work with 4DOS; you must use ECHO instead. See the PROMPT
command in the Command Reference Guide for more information.
ANSI control sequences for the prompt itself (to set colors
etc.) will work properly.
4DOS Reference Manual Copyright 1991, JP Software Inc. 12
8) If you are explicitly setting COMSPEC in AUTOEXEC, you
should delete this line or place a REM in front of it if you
want to use 4DOS as your secondary shell. 4DOS will
automatically set the COMSPEC to C:\4DOS.COM.
Automatic Installation
You must have a diskette version of 4DOS to use automatic
installation. To install 4DOS automatically from a diskette
in drive A to a hard disk configured as drive C, insert the 4DOS
Shareware Disk in drive A and type:
a:install
If you need to install from a drive other than drive A: or to a
drive other than drive C:, use the following command:
x:install x y
where x is the drive containing the 4DOS shareware disk, and y is
the drive on which you want to place the installed copy of 4DOS.
INSTALL will prompt you for your desired configuration, copy the
necessary files to your boot disk, and create some new lines for
CONFIG.SYS. These new lines, in the file CONFIG.4D, must be
merged with your existing CONFIG.SYS file before rebooting your
system to start 4DOS.
NOTE: You may want to edit the new CONFIG.SYS lines if you have
an unusual configuration, or if you want to modify the default
values.
If you have a registered copy of 4DOS, during the installation
process INSTALL will prompt you to insert the registered disk
in order to "brand" your copy of 4DOS with your name and serial
number.
4DOS Reference Manual Copyright 1991, JP Software Inc. 13
DOS Shells Explained
This section gives an overview of what "DOS shells" (as discussed
in this manual) are, and of primary and secondary shells. This
information is important in understanding how to install and
configure 4DOS. If you already understand these concepts, go on
to the next section.
In the PC world the term shell has come to mean any program that
gives you the capability to execute DOS commands and run
programs. We will use it more precisely to mean the system
command interpreter, the program which reads your keystrokes at
the DOS prompt and interprets them, allowing you to execute
internal commands and run external programs. Before 4DOS,
virtually all PCs using DOS used COMMAND.COM as the shell.
When your system is started, the last thing the system startup
software does is to load a copy of the shell program into memory
and give it control. This program is called the primary or root
shell. It executes AUTOEXEC.BAT, displays the command line
prompt and processes your commands.
The primary shell is the program that executes most of the
commands you enter, either as internal functions (e.g., the DIR
command), or by loading and executing other programs (e.g., a
word processing program).
The text file CONFIG.SYS, stored in the root directory of your
boot disk, tells MS-DOS how to start: what device drivers to
load, how many open files to allow, etc. The SHELL statement in
CONFIG.SYS determines what program is loaded as the primary
shell. If you don't have a SHELL statement, MS-DOS will load
COMMAND.COM as the primary shell. However, any properly written
program can be loaded in place of COMMAND.COM. This is the
normal method for loading 4DOS.
Now, suppose from inside your word processor you invoke the
"shell to DOS" option, to execute some commands without having to
save your files and exit first. When the prompt comes up, you
are running a secondary shell; the word processor has loaded a
shell program into memory to perform commands. When you type the
EXIT command, the secondary shell terminates and control is
returned to the word processor.
The same kind of sequence is used by many programs which run
other programs or execute MS-DOS commands: the program loads a
copy of the command processor (a secondary shell) and passes a
command to it to execute a command or another program. For
example, a hard disk manager which allows you to copy files may
invoke a secondary shell and pass a COPY command to it to
actually perform the copy.
4DOS Reference Manual Copyright 1991, JP Software Inc. 14
Multitasking or task switching systems may also use secondary
shells to load and execute the programs you specify in each of
the windows or partitions they support. For example, DESQview
will load a secondary shell to execute your program under some
conditions, and will execute the program directly under other
conditions (see the DESQview manual for details).
In all of these situations, the secondary shell need not be the
same program as the primary shell. The two shells are completely
independent, occupy different areas of memory, and generally have
little interaction with each other. Both COMMAND.COM and 4DOS can
work as primary and/or secondary shells.
The COMSPEC Environment Variable
A variable in the MS-DOS environment, COMSPEC, determines which
program is loaded as the secondary shell, just as the SHELL
command in CONFIG.SYS specifies the primary shell program. The
COMSPEC variable is set at startup time to point to the primary
shell program. It can be modified at any time with the SET
command. If COMSPEC does not point to a valid command processor
(including the correct drive and directory), programs attempting
to shell to MS-DOS will fail.
In 4DOS, COMSPEC is set at system startup to d:\4DOS.COM, where
d: represents the drive the system was started from. In
COMMAND.COM, COMSPEC is set to d:\COMMAND.COM.
If 4DOS is your primary shell, and 4DOS.COM and 4DOS88.EXE (or
4DOS286.EXE) are not stored in the root directory of the boot
drive, you MUST set COMSPEC yourself in AUTOEXEC.BAT with the
proper drive and directory for 4DOS.COM and the 4DOS EXE files.
If COMSPEC is not set correctly, you will not be able to shell
out to 4DOS or execute external commands from within your
application programs. For example, if your 4DOS.COM and
4DOS88.EXE or 4DOS286.EXE files are in D:\BIN\4DOS, put the
following command in AUTOEXEC.BAT:
set comspec=d:\bin\4dos\4dos.com
Note that COMSPEC contains only the name of the shell program.
Any options to be passed to secondary 4DOS shells must be set
separately in 4DSHELL (see below).
NOTE: A few ill-behaved programs ignore COMSPEC, and explicitly
load COMMAND.COM as a secondary shell. Although it is possible
to rename 4DOS.COM to COMMAND.COM to handle most of these cases,
we recommend you keep a copy of COMMAND.COM on your system as it
may be needed for other purposes.
4DOS Reference Manual Copyright 1991, JP Software Inc. 15
Some versions of COMMAND.COM permit specification of an alternate
path for COMMAND.COM as an argument on the SHELL= line in
CONFIG.SYS, and this path is used to set the COMSPEC. This is
not a documented feature of COMMAND.COM, and is not supported by
4DOS.
4DOS Reference Manual Copyright 1991, JP Software Inc. 16
Manual Installation and Configuration Options
These instructions assume that you are installing 4DOS on a hard
disk with drive letter C, and that you will be placing the 4DOS
system files in the root directory of that disk. If you need to
place the files on another drive or directory (for example, on a
floppy disk system), you will need to adjust the parameters.
The first step in installing 4DOS is to copy the files from the
4DOS disk or compressed file to your boot disk. If you have a
diskette copy of 4DOS, see the README.DOC file on the diskette
for information on exactly how the files are stored.
Copy (or decompress) the following 4DOS system files to the root
directory of your boot disk:
KEYSTACK.SYS
4DOS.COM
4DOS88.EXE, if your system has an 8086 or 8088 CPU (this
applies to most PC and XT systems)
4DOS286.EXE, if your system has an 80186, 80188, 80286,
80386, 80486, or NEC V20 or V30 CPU (this applies to all
AT and 386/486 systems, and some other systems with
accelerator boards or replacement CPU chips)
If you are in doubt about your CPU type, use 4DOS88.EXE until you
can determine the CPU type definitively (see the _CPU variable in
Environment Variables). 4DOS88.EXE will work with all PCs.
Copy (or decompress) the files HELP.EXE and DOS.HLP to a
directory included in your path (i.e. one listed in the PATH
statement in AUTOEXEC.BAT).
Copy (or decompress) the files 4DOS.DOC, README.DOC, COMPAT.DOC,
and ALIASES to any directory you choose, if you wish to have them
available on-line permanently, or temporarily in order to print
them.
4DOS Reference Manual Copyright 1991, JP Software Inc. 17
4DOS Memory Usage
When installing 4DOS you must decide whether you want to run in
swapping mode or memory-resident mode.
Swapping mode is recommended for most users. In this mode a
small part of 4DOS (the resident portion, less than 4K in size,
from the file 4DOS.COM) resides permanently in low memory. The
remainder of 4DOS (the transient portion, about 70K in size, from
the file 4DOS88.EXE or 4DOS286.EXE), resides at the end of normal
MS-DOS memory, and is swapped out to XMS, EMS, or disk while your
applications are running. This swapping is very fast, especially
if XMS or EMS memory or a RAM disk is available, and it allows
you to have the power of 4DOS, yet keep most of your memory
available for applications.
COMMAND.COM uses a similar approach to keep its resident portion
in low memory and its transient portion at the end of DOS memory.
It does not retain information while applications are running, so
it does not use a swap area. The resident portion of COMMAND.COM
is slightly larger than that of 4DOS. The transient portion is
smaller (about 35K) as COMMAND.COM has far fewer features and
capabilities than 4DOS.
The resident portion of 4DOS takes about 10K of memory to load
(later reduced to less than 4K), and the transient portion 70K,
so you must have about 80K of free memory to load 4DOS in
swapping mode (82K for 4DOS88).
COMMAND.COM requires about 40K of free memory to load. If you
find you are able to load COMMAND.COM as the secondary shell from
a particular program, but are unable to load 4DOS, it is probably
because you have more than 40K but less than 80K of free memory,
or because COMSPEC and/or 4DSHELL (see below) are set
incorrectly.
Memory resident mode is recommended only on systems (older PCs
and some laptops) which have no hard disk, XMS or EMS memory, or
RAM disk. On such systems the only swap area available is a
floppy disk, which is unacceptably slow. In memory-resident
mode, all of 4DOS is loaded permanently into low memory; the
memory required is about 70K for 4DOS286.EXE, or 72K for
4DOS88.EXE.
4DOS Reference Manual Copyright 1991, JP Software Inc. 18
Setting up CONFIG.SYS
In order to install 4DOS you must modify the CONFIG.SYS file.
First, create a SHELL command to tell MS-DOS to load 4DOS as the
command processor. The format of the command is:
SHELL=d:\path\filename [options]
where d:\path is the drive and directory where the primary shell
program is stored, filename is the full name of that program, and
[options] is any option or parameter values for 4DOS. (See 4DOS
Startup Options.) The options are passed to the program just as
if they had been typed on the command line.
When loading 4DOS, the filename part of the command should be
4DOS.COM. For example, the simplest SHELL command which will
load 4DOS properly is:
SHELL=C:\4DOS.COM /P
This loads 4DOS in swapping mode (4DOS determines the optimal
swapping method), with default sizes for the environment, alias
list, and history list. The /P tells 4DOS it is the primary
shell.
Use an editor to edit or create your CONFIG.SYS file, and set up
your SHELL command as shown above, along with any additional
options you need (see next section). If you already have a SHELL
command for COMMAND.COM, remove it. Examples of SHELL commands
for different systems are given in 4DOS Startup Options.
CAUTION: Due to a bug in all versions of MS-DOS and PC-DOS, the
SHELL command in CONFIG.SYS may not contain more than 33
characters following the name of the shell program (i.e.,
beginning with the first character of the [options] in the
example above). If the line is too long, the options will not be
passed properly to 4DOS, and a variety of errors can occur. You
can usually set all of the 4DOS options without exceeding this
limit, provided you keep 4DOS88.EXE / 4DOS286.EXE in the root
directory of your boot disk. If you need a longer SHELL command
line, 4DOS provides the @filename option (see 4DOS Startup
Options).
In addition to the shell command, if you want to use the 4DOS
KEYSTACK command (see Command Reference), you must place a line
in CONFIG.SYS to load the 4DOS KEYSTACK device driver. This line
should read:
device=c:\keystack.sys
4DOS Reference Manual Copyright 1991, JP Software Inc. 19
Loading 4DOS Under DOS 2
While we recommend the use of MS-DOS 3.1 or above, 4DOS can be
used with MS-DOS 2. In MS-DOS 2, certain functions require
COMMAND.COM to be loaded as the primary command processor, so you
must load COMMAND.COM first, then load 4DOS. Assuming all files
are in the root directory of drive C, the SHELL command to do
this is:
shell=c:\command.com /c 4DOS [options]
The [options] are defined in 4DOS Startup Options, and should
include /P even though 4DOS is not (technically) the primary
shell. If /P is left off, AUTOEXEC.BAT will not be run.
Note that due to the /C 4DOS on the SHELL line, fewer options can
be used before running into the 33-character limit discussed
earlier. For this reason the "@filename" option may be necessary
when loading 4DOS under DOS 2.
Loading 4DOS in the OS/2 DOS Compatibility Box
4DOS can be loaded in the OS/2 MS-DOS compatibility box, but you
will be limited to either disk swapping or memory resident modes.
(The compatibility box does not support EMS or XMS.)
4DOS Reference Manual Copyright 1991, JP Software Inc. 20
4DOS Startup Options
This section describes the options that can be included on the
SHELL command in CONFIG.SYS, and/or used for secondary shells
(see 4DSHELL). The same options can also be used when you start
4DOS in a window of a multitasking or task switching environment
such as DESQview or Windows, or from the command line or a batch
file.
@d:\path\filename
Stop processing input from the command line, and switch to
the specified file. Any characters on the line after this
option will be ignored. The file may contain any number of
lines specifying additional 4DOS options, and may be up to a
total of 255 characters long. This option allows you to get
around the 33-character limit on options in the SHELL command
by placing 4DOS options in a separate file.
/A:n
Set the alias list size. The range of allowable alias list
sizes for all shells is 256 - 32000 bytes. The default
value for all shells is /A:1024. The incremental syntax
shown with /E below (/E+n) may also be used with /A.
/C cmd
Load a transient copy of 4DOS, execute cmd, and then return
to the parent command processor. This option is used by
some application programs to start the command processor,
execute a command, and automatically return to the program.
It should never be used in the SHELL statement.
/E
Set the environment size. The range of allowable
environment sizes for all shells is 256 - 32000 bytes.
There are two formats for this option:
/E:n
n is the size of the environment in bytes. The default
for the primary shell is /E:512.
/E+n
Set the environment size to the amount of space
previously used, plus n bytes. This allows you to
guarantee a certain amount of free space in a secondary
shell environment. The default for secondary shells is
/E+128; the minimum increment allowed is 128 bytes.
With either format, appending a U after the size (for
example, /E:512U) will cause 4DOS to load the master
environment into an XMS UMB. (See the /U option below for
more information on UMBs.) This reduces low-memory
requirements, but may not be compatible with some programs
which access the master environment. If no UMB is
4DOS Reference Manual Copyright 1991, JP Software Inc. 21
available, 4DOS displays an error message, and the
environment is put into low memory.
Appending an S after the size will swap the master copy of
the environment. This will save a small amount of DOS memory,
but will not work with any application that attempts to
modify the master environment (for example, Novell Netware).
4DOS will always ensure there is at least 128 bytes free in
a secondary shell environment, and will override your /E
parameter if necessary.
/H:n
Set the history size, where n is the size of the history
list. (The default is 1024 bytes; the range is 512-8192
bytes.)
/L:d:\path
Tells 4DOS where to find 4DOS88.EXE (or 4DOS286.EXE). The
default is the root directory of the boot drive for the
primary shell, and the path specified by COMSPEC for
secondary shells. You must use this switch if the EXE file
is not in the default location.
/P
Load 4DOS permanently, and run AUTOEXEC.BAT. 4DOS will NOT
run AUTOEXEC.BAT without a /P. This option may be placed
anywhere on the SHELL= line, but normally appears as the
last option. Do NOT use this option for secondary shells,
or you will be unable to return to the primary shell.
/S
Set the 4DOS swapping mode, as follows:
/S:B[d:\path]
Best guess swapping (default mode). 4DOS first tries
XMS memory swapping (on an 80286 or 80386), then EMS,
then disk swapping to the specified drive and directory.
Disk swapping filenames and defaults are as described
for /S:D below.
/S:D[d:\path]
Swap to disk. Creates a file 4DOSSWAP.xxx where xxx is
the current shell nesting level (000 for the primary
shell). If the drive and path are not specified, disk
swapping will default to the root directory of the boot
drive for the primary shell, and the root directory of
the drive specified in COMSPEC for secondary shells.
/S:E
Swap to EMS memory. EMS swapping requires a minimum of
80K free EMS memory for the primary shell, and 32K for
4DOS Reference Manual Copyright 1991, JP Software Inc. 22
most secondary shells; very large environment, alias
list, and history sizes will require more.
/S:N
Load 4DOS in memory-resident mode (no swapping).
/S:X
Swap to XMS (extended) memory. XMS swapping requires
an XMS device driver and a minimum of 70K of free XMS
memory; large environment, alias list, and history
sizes will require more.
If 4DOS can't access EMS or XMS memory or create the disk
swap file, it will load with swapping disabled (memory-
resident mode). 4DOS displays the type of swapping (XMS,
EMS, or disk) and the amount of swapping space used when it
starts.
If possible, 4DOS will reduce the space used to swap a
secondary shell from 68K or more to about 20K by retrieving
static information from the primary shell's swap area. This
feature will not work if the total of alias, history, and
environment sizes in the secondary shell is larger than the
total for the primary shell, or if the size of DOS memory has
been reduced when the secondary shell is started (e.g. by a
program like DESQView that reserves some space at the top
end of DOS memory).
/U
Move the resident portion of 4DOS to an XMS Upper Memory
Block (UMB). This reduces the size of the resident portion
in low memory from about 3K to 256 bytes, plus the
environment size. This option can only be used on 286 and
386 systems with software which can map memory into the 640K
to 1MB area and have 3K or more of free space in that area,
and which include an XMS driver. XMS swapping may be used
for the rest of 4DOS via /S:X, but is not required for /U to
work. If the UMB load fails, the load will continue with the
resident portion of 4DOS remaining in low memory. See
COMPAT.DOC for up to date information on the memory management
software needed to enable /U to work.
Any text on the 4DOS command line (including the SHELL= line)
following the final option will be interpreted as a startup
program command. This allows you to directly load a program
without running AUTOEXEC.BAT (and giving the user the opportunity
to break out to the MS-DOS prompt with a ^C).
For example, to load 4DOS in EMS swapping mode with a 2048
character alias list and a 2048 character command history:
shell=c:\4dos.com /s:e /a:2048 /h:2048 /p
4DOS Reference Manual Copyright 1991, JP Software Inc. 23
To load 4DOS with a 2048 character environment in disk swapping
mode, swapping to a RAM disk defined as F:
shell=c:\4dos.com /s:df:\ /e:2048 /p
To load 4DOS in "best available" swapping mode, using drive G for
disk swapping if necessary, loading the .COM and .EXE files from
the directory D:\BIN\4DOS, with a 1024 character environment, a
4096 character alias list, and a 2048 character history, and the
low-memory code moved to a UMB if possible:
shell=d:\bin\4dos\4dos.com @d:\bin\4dos\4dos.opt
The file D:\BIN\4DOS\4DOS.OPT: would contain:
/s:bg:\ /l:d:\bin\4dos /e:1024 /a:4096 /h:2048 /u /p
To load 4DOS in XMS swapping mode, with default history and
environment, and run a program called C:\UTIL\MYSHELL
automatically after the AUTOEXEC file (if any) is completed:
shell=c:\4dos.com /s:x /p c:\util\myshell
The 4DOS EXE file (4DOS88 or 4DOS286) can be loaded directly as
the primary shell, by using it as the filename in the SHELL
command; or as the secondary shell, by using it as the filename
in COMSPEC. For example:
shell=c:\4dos286.exe /e:2048 /p
When the EXE file is loaded directly, rather than via 4DOS.COM,
4DOS will be in memory-resident mode. The only options permitted
are /A:n, /E:n, /H:n, /C, and /P. Aliases will not be inherited
from a previous shell.
We do not recommend this method of loading 4DOS in most
circumstances; to load in memory-resident mode, use the /S:N
option instead. However, you may wish to use it to conserve disk
space (for example, on a laptop with no hard disk), as it does
not require 4DOS.COM to be on your disk.
4DOS Reference Manual Copyright 1991, JP Software Inc. 24
The 4DSHELL Environment Variable
When loading the primary shell, the shell name and options are
both specified by the SHELL command in CONFIG.SYS. For secondary
shells, COMSPEC specifies the shell name, but not the options.
4DSHELL is an environment variable, used by 4DOS to set the
options for secondary shells. If 4DSHELL is not defined,
secondary shells will use default values for their options. If
options are set on the command line, they will override those in
4DSHELL.
4DSHELL should normally be set in AUTOEXEC.BAT. It can contain
any of the options listed in 4DOS Startup Options, except /C and
/P. If the 4DOS EXE file is not in the directory specified by
COMSPEC, you MUST use the /L option in 4DSHELL, or secondary
shells will not start properly.
The following examples show the use of both COMSPEC and 4DSHELL
to configure your system properly for secondary shell operation.
To load 4DOS.COM and the EXE file from C:\, use EMS swapping in
secondary shells, and guarantee 512 bytes of free environment
space:
[no COMSPEC setting necessary]
set 4dshell=/s:e /e+512
To load 4DOS.COM from C:\BIN and the 4DOS EXE file from D:\BIN,
use best guess swapping (default), and move the resident portion
of secondary shells to an XMS UMB if possible:
set comspec=c:\bin\4dos.com
set 4dshell=/l:d:\bin /u
AUTOEXEC and 4START
The AUTOEXEC.BAT file contains DOS commands to be AUTOmatically
EXECuted by the primary shell when it starts. It is executed
before you are given control at the prompt. The /P switch MUST
be on the SHELL= line in CONFIG.SYS for AUTOEXEC.BAT to be
executed. AUTOEXEC cannot be a .BTM file.
If you do not have an AUTOEXEC.BAT file, COMMAND.COM will prompt
you for the current date and time. 4DOS will not; it will simply
transfer you immediately to the 4DOS prompt.
4START is an optional batch (.BAT or .BTM) file of 4DOS commands
to be executed whenever 4DOS is started, whether as a primary or
secondary shell. This makes it a convenient place to put
configuration commands such as SETDOS, to make 4DOS operate in
the mode you want regardless of whether you are in a primary or
secondary shell. In the primary shell, 4START is executed before
AUTOEXEC.BAT.
4DOS Reference Manual Copyright 1991, JP Software Inc. 25
You should not load any memory-resident programs (TSRs) from the
4START file, because 4DOS will attempt to load them every time it
starts a new shell.
You shouldn't load aliases from 4START, since 4DOS will pass them
automatically to secondary shells.
4DOS and COMMAND.COM
In virtually all circumstances you will want to load 4DOS as your
primary and secondary shell. However, there are a handful of
ill-behaved programs which dynamically modify COMMAND.COM, or
otherwise interact with COMMAND.COM in a non-standard way, which
may require you to load COMMAND.COM in order to work properly.
In some circumstances, to run a particular program you may need
to load a copy of COMMAND.COM from within 4DOS, then run the
program. In very rare circumstances, you may need to load
COMMAND.COM as the primary shell and then load 4DOS. An
explanation of both techniques is included in Appendix E and the
file COMPAT.DOC, along with a list of the programs known to
require them.
You may also find that in some cases, when there is a need to
shell to DOS with very little memory available, you wish to use
COMMAND.COM as your secondary shell, while 4DOS is the primary
shell. To do so, simply set your COMSPEC to point to
COMMAND.COM.
If you wish to run a copy of COMMAND.COM from the 4DOS prompt for
testing or other purposes, be sure to set the COMSPEC to point to
COMMAND.COM first. If you don't, and an application overwrites
the COMMAND.COM transient portion, COMMAND.COM may be unable to
reload itself, and will give an error message and return to 4DOS.
4DOS Reference Manual Copyright 1991, JP Software Inc. 26
Using 4DOS
This section briefly reviews 4DOS features, and provides some
examples of how 4DOS can help improve your productivity, and make
your computer easier to use. It also documents the features of
4DOS which are not related to specific commands, such as command
line editing, command history, command syntax, and batch files.
Starting 4DOS
Whenever 4DOS is loaded, it searches the boot directory for the
file 4START.BTM or 4START.BAT, and executes it if found. If 4DOS
is started with the /P option, it will then execute AUTOEXEC.BAT.
Because 4START is always executed when 4DOS starts, it provides a
convenient place to put the 4DOS configuration commands (for
example, SETDOS parameters) that would otherwise not be set when
executing a secondary copy of 4DOS. (For example, when shelling
out to MS-DOS from within a program.) See the Command Reference
Guide for more information on SETDOS.
When setting up 4START and AUTOEXEC.BAT, we recommend you break
up the work to be done into smaller batch files. In particular,
if you put the aliases and environment variables into separate
batch files and use CALL to invoke them, you can edit and
reinvoke them later without having to reboot the system.
4DOS Reference Manual Copyright 1991, JP Software Inc. 27
Command Line Editing
The following keys have special meanings when editing command
lines (the caret ^ means press the Control key together with
the specified key):
Left Arrow Move the cursor left one character.
Right Arrow Move the cursor right one character.
Up Arrow Recall the previous command from the history list,
or match a partial command entry with a history
list entry.
Down Arrow Recall the next command from the history list, or
match a partial command entry with a history list
entry.
^Left Arrow Move the cursor left one word.
^Right Arrow Move the cursor right one word.
Home Move the cursor to the beginning of the line.
^Home Delete from the beginning of the line to the
character preceding the cursor.
End Move the cursor to the end of the line.
^End Delete from the cursor to the end of the line.
Ins Toggle between insert and overstrike mode.
Del Delete the character at the cursor.
Backspace Delete the character to the left of the cursor.
CR or LF Execute the command.
Esc Erase the entire line.
^L Delete the word to the left of the cursor.
^R or ^Bksp Delete the word to the right of the cursor.
^C Cancel the command.
^D Delete the history list entry, erase the line, and
display the previous history entry.
^E Go to the end of the history list and display the
entry.
^K Save the command to the history list, and erase
the line.
F1 Call the on-line help (HELP.EXE).
F3 Repeat or complete the previous line from the
history list (as in COMMAND.COM)
F8, F9 & F10 F9 scans the filename (including the wildcard
(TAB=F9, characters * and ?) at or immediately to the left
shift-TAB=F8) of the cursor position, and replaces it with the
first matching filename. Pressing F9 again
substitutes the next filename; pressing F10
appends the next filename at the current cursor
position. Pressing F8 gets the previous
filename. If you don't enter an extension, F9
will append *.* to the filename; otherwise, F9
will append *. See Command History and Recall
for more information on filename completion.
Alt-255 You can enter characters that would normally be
interpreted by the line editor as a command (for
example, ^D) by preceding them with an Alt-255.
(Hold down the Alt key and enter 255 on the
numeric keypad.)
Anything else Enter that character at the cursor position.
4DOS Reference Manual Copyright 1991, JP Software Inc. 28
Command History and Recall
4DOS saves each command into the command history list as it is
entered (except when executing a batch file), allowing you to
display, recall, search, and modify previous commands.
The history list size is determined by the /H parameter at
startup time (see Installation). The history is a circular list;
when the history list is full, 4DOS discards the oldest
command(s) before adding the newest.
The command history list can be displayed or cleared with the
HISTORY command. The /H option in SETDOS allows you to enable or
disable the history saves, and to specify a minimum length to
save. (See the Command Reference Guide for more information on
HISTORY and SETDOS.) You can prevent a command line from being
saved in the history list by beginning it with an @.
The simplest use of the command history is to repeat commands
exactly. For example, you might enter the command:
dir /2p b:*.wks b:*.doc
and then move some files to or from drive B. When you're
through, you want to repeat the DIR command. Just press the up-
arrow repeatedly to scan back through the history list; when the
DIR command appears, press ENTER to reexecute it.
After you've found the command, you can also edit it before
pressing ENTER. This provides a simple means of executing a
series of commands that differ only slightly from each other.
Another powerful feature is command completion, which searches
the command history for the last command that begins with the
characters you entered. In the above example, you can quickly
recall the DIR command by typing DI, and pressing the up arrow.
4DOS will display the most recent command in the history list
that begins with DI. Pressing the up arrow again will display
the next most recent match. Typing DI and pressing the down
arrow key instead would search for the oldest matching command in
the history list. 4DOS will beep if there are no matching
commands.
4DOS Reference Manual Copyright 1991, JP Software Inc. 29
4DOS also offers filename completion. For example, suppose you
want to copy a file. You remember that the name starts with AU,
but you can't remember the rest. Enter:
copy au
and press the F9 key. The first filename that starts with AU
will be inserted in the command line. If it's the right file,
simply complete your command. If it's not, press F9 again to
substitute the next matching filename. If you go past the
filename(s) you wanted, pressing the F8 key will return the
previous matching filename. The F10 key saves the current
filename, and then appends the next matching filename to the
command line. You can use the wildcard characters (* and ?) in
the filename. 4DOS will beep when there are no more matching
filenames.
Multiple Commands
You may enter multiple commands on a single line. The default
command separator is a caret (^). For example, the following
command displays a directory and then copies files to the root
directory on drive A:
dir *.bat ^ copy *.bat a:\
The command separator character can be changed by setting the
COMPOUND variable (see the SETDOS command in the Command
Reference Guide).
Conditional Commands
When an internal or external command finishes, it returns a
result, called the exit code. The conditional commands allow you
to perform tasks based upon the previous command's exit code.
(See also the IF ERRORLEVEL and IFF ERRORLEVEL commands in the
Command Reference Guide.)
If two commands are separated by && (AND), the second command
will be executed only if the first returns an exit code of 0.
If two commands are separated by || (OR), the second command will
be executed only if the first returns a non-zero exit code.
NOTE: All 4DOS internal commands return an exit code (0 if
successful, or non-zero for an error return), but not all
external programs do. Conditional command behavior will be
unpredictable for programs that don't explicitly return an exit
code.
4DOS Reference Manual Copyright 1991, JP Software Inc. 30
For example, if the BACKUP operation fails, the files will not be
erased:
backup c:\ a: /s && global erase *.bak *.lst
If the BACKUP operation fails, then ECHO will display a message:
backup c:\ a: /s || echo Error in the backup!
Escape Character
4DOS has a user-definable escape character (a character which
gives the following character a non-standard meaning, not the
same as the ASCII ESC). The default is ^X (control-X, which will
be displayed as an up arrow ), but another character can be used
by setting the ESCAPE variable (see the SETDOS command in the
Command Reference Guide). 4DOS assumes special meanings when
these characters follow the escape character on the command line:
b backspace
e the ASCII ESC character (27 decimal)
f formfeed
n linefeed
r carriage return
t tab
Any other character following the escape character is copied
directly to the command line and the escape character is removed.
This allows you to suppress the normal interpretation of special
characters (such as ? * / \ | ` > < and &).
For example, to send a form feed followed by the sequence ESC Y
to the printer:
echo feY > prn
4DOS Reference Manual Copyright 1991, JP Software Inc. 31
Command Echoing
Like COMMAND.COM, 4DOS defaults to ECHO ON in batch files. To
prevent a line from being echoed, preface it with the @ symbol.
You can tell 4DOS to default to ECHO OFF by setting the variable
VERBOSE to 0 (see the SETDOS command in the Command Reference
Guide).
4DOS also offers command echoing during keyboard input. If ECHO
is set ON from the command line, the fully parsed and expanded
command (including alias and variable expansion) will be
displayed before it is executed. If the command line contains
multiple commands, each command is echoed separately just before
it is executed.
Note that the command line echo state and batch file echo state
are independent. Turning echo on or off inside a batch file will
not affect command line echoing, and vice versa.
Argument Quoting
4DOS normally parses command line arguments by searching for
white space (blanks, tabs, and commas). Command line arguments
enclosed in back quotes (`) or double quotes (") may contain
white space. No special processing (alias or variable expansion,
and I/O redirection) will be performed on expressions enclosed in
quotes, except variable expansion WILL be performed inside double
quotes.
4DOS will strip back quotes from the command line before
executing the command. Double quotes will be passed through to
the command.
For example, suppose the batch file QUOTES.BAT contains the
following commands:
@echo off
echo Arg1 = %1
echo Arg2 = %2
echo Arg3 = %3
and that the environment variable %FORVAR has been defined as:
set %forvar=for
Entering the command:
quotes `Now is the time %forvar` all good
produces the following output:
Arg1 = Now is the time %forvar
Arg2 = all
Arg3 = good
4DOS Reference Manual Copyright 1991, JP Software Inc. 32
and entering the command:
quotes "now is the time %forvar" all good
produces the following output:
Arg1 = "Now is the time for"
Arg2 = all
Arg3 = good
When an alias is defined in a batch file or from the command line
(see Aliases), its argument should be enclosed in back-quotes to
prevent the expansion of parameters, variables, and multiple
commands until the alias is invoked. Back quotes should NOT be
used when defining aliases to be read in an ALIAS /R file.
Batch Files
COMMAND.COM executes batch files by opening the file, reading one
line, saving the position, closing the file, executing the line,
opening the file, moving to the saved position, reading the next
line, etc. This scheme has two advantages: batch files can
modify themselves dynamically, and they can extend across
multiple disks. It also has one disadvantage: batch files run
very slowly.
For the sake of compatibility, 4DOS processes .BAT files the same
way. But 4DOS also offers a much faster approach, called Batch
to Memory (.BTM). Since a .BTM file is loaded entirely into RAM
before it is executed (requiring only one disk access), .BTM
files run two to five times faster than .BAT files (even faster
on floppy disks). For very small batch files the difference
between .BAT and .BTM files will be negligible, but for large
files or ones with loops, a .BTM will run nearly as fast as an
alias. Most .BAT files can be renamed to a .BTM extension and
immediately realize a significant performance improvement.
The maximum size of a .BTM file is 64K bytes.
You should not use a .BTM file (or a .BAT file which is CALLed
from a .BTM file) to load memory-resident (TSR) programs. If you
do, the memory used for the .BTM file will be located below the
TSR. When the .BTM file exits, this memory will be freed and you
will be left with a "hole" in memory. This is not harmful, but
wastes memory.
4DOS also offers an additional "Cancel ALL" option for ^C
handling in batch files. If you press ^C or ^BREAK while in a
batch file, 4DOS will prompt:
Cancel batch job ? (Y/N/A) :
4DOS Reference Manual Copyright 1991, JP Software Inc. 33
Pressing N will continue batch processing at the next line.
Pressing Y will end the current batch file and return to the
calling batch file (if any). Pressing A will cancel all batch
file processing, regardless of the nesting level (see CALL and
CANCEL in the Command Reference Guide) and return to the command
prompt.
Batch files may be "nested" (batch file A CALLs batch file B
which CALLS batch file C, etc.) up to 8 levels deep.
Batch File Variables
Batch file variables are only active inside a batch file. They
are referenced as %0 to %127, and expand to the matching argument
on the command line that started the batch file. The parameter
%n& is a special case, and expands to all arguments in the
command line tail, starting at argument number n. If n is not
specified, it defaults to 1 (so %& expands to all arguments in
the command line tail).
The batch variable %# expands to the number of command line
arguments, not including %0 (the batch file name).
Note that the SHIFT command will shift both the numbered
variables (%0, %1, etc.) and the %n& and %# variables.
4DOS Reference Manual Copyright 1991, JP Software Inc. 34
Aliases
Much of the power of 4DOS comes together when using aliases. An
alias is a new name for a command or combination of commands.
Aliases are defined with the ALIAS command, and removed with the
UNALIAS command. Aliases are expanded before the command line is
broken up for multiple commands, redirection, and conditional
commands. Aliases may be nested; i.e., an alias can refer to
another alias, but they cannot refer back to themselves.
The alias name is limited to no more than 80 characters, and the
alias argument to no more than 255 characters.
The simplest type of alias is to give a new name to an existing
command. For example:
alias up cd ..
defines the alias UP to mean "change to the parent directory".
Aliases can also create a customized version of a command. For
example, the 4DOS DIR command allows a directory to be sorted in
various ways. The alias:
alias de dir /oe /p
defines the alias DE to mean "sort the directory by extension,
pausing after each page."
Aliases can also be used to execute multiple commands; when used
this way they act like very fast, in-memory batch files. For
example, entering the command:
alias w `pushd c:\wp ^ wp %& ^ popd`
defines the alias W to mean "save the current directory, change
to the WP directory on C, run the WP program passing it all of
the arguments on the command line following the alias name, and
when finished, restore the original directory." The back quotes
are required to tell 4DOS this is a single alias with three
commands, rather than three commands on a single line (see
Multiple Commands).
You can stop alias expansion by prefacing the alias with an
asterisk (*). This allows you to use aliases to define commands
as variations of themselves, or to rename internal commands to
avoid conflicts with external programs. For example, the alias
definition:
alias global global /I
will fail with an "alias loop" error message, but the alias:
alias global *global /I
4DOS Reference Manual Copyright 1991, JP Software Inc. 35
will work properly. You can also use this feature to rename a
4DOS internal command (for example, if you have an external
program of the same name). The following alias definitions
rename the LIST command to DISPLAY, and call an external program
for LIST:
alias display *list
alias list c:\util\list.com
Alias names can be truncated by including an asterisk (*) in the
alias name. For example, if you have an alias defined as:
alias wher*eis dir /dp
you can refer to it as wher, where, wherei, or whereis.
Alias definitions can include replaceable parameters, like those
in batch files. Alias parameters are referenced as %1 to %127,
and expand to the matching command line argument. The parameter
%n& is a special case, and expands to all arguments in the
command line tail, starting at argument number n. If n is not
specified, it defaults to 1 (so %& expands to all arguments in
the command line tail).
If an alias has replaceable parameters, 4DOS will delete command
line arguments up to and including the highest referenced
argument. For example, if you have an alias which refers only to
%1 and %4, then the first and fourth arguments passed to the
alias will be used, the second and third arguments will be
discarded, and any additional arguments beyond the fourth will be
appended to the end of the alias. If an alias has no replaceable
parameters, all of the command line arguments will be appended to
the alias.
For example, the following alias will change directories, perform
a command, and return to the original directory:
alias in `pushd %1 ^ %2& ^ popd`
When this alias is invoked with:
in c:\comm mycomm /xmodem /2400
it is expanded into the following three commands:
pushd c:\comm
mycomm /xmodem /2400
popd
4DOS Reference Manual Copyright 1991, JP Software Inc. 36
The distribution disk includes a sample alias file (ALIASES)
which demonstrates a number of useful predefined aliases.
See the ALIAS and UNALIAS commands in the Command Reference Guide
for more information and examples.
Executable Extensions
4DOS provides a means to specify a program to be invoked when a
filename which does not have a .COM, .EXE, .BTM, or .BAT
extension is entered as the first argument on the command line.
For example, you could start your text editor when a text file is
specified, or your spreadsheet program when a worksheet file is
specified.
4DOS uses environment variables to define what program or batch
file to run for a particular extension. The syntax of the SET
command to define an executable extension is:
SET .ext=d:\path\program [options]
where .EXT is the file extension, D:\PATH\PROGRAM is the full
name of the program or batch file to be called, and [options]
are any startup options you want to specify for the program. The
file to be executed must be a .COM, .EXE, .BTM, or .BAT file; it
cannot be an alias or internal command.
For example, the following command would define BASICA.COM as the
processor for .BAS files:
set .bas=c:\dos\basica.com
The following command would define B.EXE (the Brief text editor)
as the processor for .C files:
set .C=c:\brief\b.exe -Mxyz
If you have a file HELLO.C, and enter the command:
hello -i30
4DOS expands the command line to:
c:\brief\b.exe -Mxyz hello.c -i30
4DOS Reference Manual Copyright 1991, JP Software Inc. 37
Note that 4DOS inserts the value of the environment variable at
the beginning of the line, including any options, then appends
the original command name (i.e., the file name, with extension
added if necessary), and the remainder of the original command
line.
4DOS searches for external commands in the following order:
.COM, .EXE, .BTM, .BAT, and executable extensions (in the order
they appear in the environment) in the current directory, and
then in each subdirectory specified by the PATH environment
variable.
4DOS Reference Manual Copyright 1991, JP Software Inc. 38
Keystack
The KEYSTACK command can be used in aliases and batch files to
feed keystrokes to application programs. The most common use of
KEYSTACK is to have a program take certain actions when it
starts. For example, when the alias (this should be entered on
one line):
alias 321 `keystack 0 13 0 13 0 13 0 13 0 13 "/fr" 0 "%1" 13 ^
123`
is executed as:
321 February
it loads Lotus 1-2-3, skips the startup screens, and loads the
spreadsheet FEBRUARY.WK1.
KEYSTACK can store up to 255 characters, enough keystrokes to
cause a program to do an entire operation and exit. For example,
the following alias DRPT will run a dBASE report called TIMEREP
in the directory DATA (this should be entered on one line):
alias drpt `pushd c:\data ^ keystack "use times index times"
13 "report form timerep to print" 13 "quit" 13 ^ dbase ^
popd`
See the Command Reference Guide for more information on KEYSTACK.
KEYSTACK.SYS is a small device driver invoked in your CONFIG.SYS
file (see Installation) and used to support the KEYSTACK command.
You must have KEYSTACK.SYS installed to use the KEYSTACK command.
4DOS Reference Manual Copyright 1991, JP Software Inc. 39
Environment Variables
Environment variables are defined with the SET command. (See the
Command Reference Guide for more information on SET.)
Environment variables are expanded before the command line is
broken up for multiple commands, redirection, and conditional
commands, but after alias expansion has been done.
Variables are referenced in a command by starting the variable
name with a percent sign (%). Two percent signs in a row (%%)
signify a percent sign character. An environment variable name
is terminated by either another percent sign, or by an invalid
character (see below). To pass a variable name (instead of the
value) to a command (for example, in INKEY or INPUT), you must
precede it with two percent signs.
Environment variable names may be composed of any alphanumeric
character, plus the underscore (_) and $ characters.
For example:
c:\> set start=c:\wordproc\myfiles\memos
c:\> dir /w %start
In addition to the standard variable name characters, you can
force 4DOS to accept any sequence of characters as a valid
variable name by enclosing it in square brackets. For example:
%[AB##1]
refers to an environment variable named AB##1.
There are some variable names that have special meanings in 4DOS.
Only PATH, CMDLINE and TMP are actually stored in the
environment; the remainder are internal to 4DOS, and cannot be
viewed or modified with SET or ESET. The internal variable names
are checked after variable expansion, so they can be overridden
by creating an environment variable of the same name.
? returns the exit code of the last external program (see
ERRORLEVEL). This allows you to save an exit code into
another variable and then process it later, or to see what
a program is actually returning.
PATH tells 4DOS where to search for executable files (.COM,
.EXE, .BTM and .BAT) not in the current directory. Some
applications also use the PATH variable to find their
files.
CMDLINE is the fully expanded 255-character command line. You
can access it from an external program by searching the
environment.
4DOS Reference Manual Copyright 1991, JP Software Inc. 40
TMP specifies where 4DOS should put the temporary pipe files
(see Redirection).
_BG is the screen background color at the current cursor
position.
_COLUMNS is the width of the screen
_CPU is the cpu type, returned as a string:
86 8086 and 8088
186 80186 and 80188
200 NEC V20 and V30
286 80286
386 80386 and 80486
_CWD is the current directory in the format d:\pathname.
_CWDS has the same value as CWD, except it ensures the pathname
ends in a backslash (\).
_CWP is the current directory in the format \pathname.
_CWPS has the same value as CWP, except it ensures the pathname
ends in a backslash (\).
_DATE contains the current system date, in the format mm-dd-yy
(U.S.), dd-mm-yy (Europe), or yy-mm-dd (Japan).
_DISK is the current disk (for example, C).
_DOSVER is the current MS-DOS version (for example, 3.3).
_DOW is the day of the week as a string (Mon, Tue, etc.)
_FG is the screen foreground color at the current cursor
position.
_NDP is the numeric data processor (coprocessor) type, returned
as a string:
0 no coprocessor is installed
87 8087
287 80287
387 80387
_ROWS is the height of the screen
_SHELL is the current shell nesting level (in swapping mode).
The root shell is 0. If you are not in swapping mode,
_SHELL returns 99.
4DOS Reference Manual Copyright 1991, JP Software Inc. 41
_TIME contains the current system time in the format hh:mm:ss .
The separator character may vary depending depending upon
your country information - see CHCP in the Command
Reference Guide).
Variable Functions
4DOS Version 3 introduces a new type of environment variable.
Called Variable Functions, they take one or more arguments (which
can be environment variables or variable functions themselves),
and return a value. Like all environment variables, variable
functions must be preceded or surrounded by % signs when used.
The variable functions are:
@eval[expression] - evaluate an arithmetic expression. It
supports parentheses, addition, subtraction, multiplication,
division, and modulo (%%). The expression can contain envi-
ronment variables, including other variable functions. The
elements of the expression and the result are integers between
-2,147,483,640 and +2,147,483,647. For example, if the value
of the variable "a" is 5, then %@eval[(%a*4)-2] returns 18.
@ext[filename] - returns the file extension (without the
leading period)
@full[filename] - returns the fully qualified path name
@index[string1,string2] - returns the position of string2 within
string1. The first position in string1 is numbered 0. If
there is no match, the function returns -1.
@len[string] - returns the length of the string
@line[filename,n] - returns line "n" of the specified file. (The
first line is line 0.)
@lower[string] - returns the string shifted to lower case
@name[filename] - returns the filename only (no path or extension)
@path[filename] - returns the path only (including the trailing
backslash)
@search[filename] - searches for the filename, using the PATH
environment variable, and appends an extension (.COM, .EXE,
.BAT, .BTM, or executable extension) if one wasn't specified.
@substr[string,start,length] - returns a substring, starting at
the position start and continuing for length characters. If
length is negative, the start is relative to the right side.
(The first character is 0.) For example, to get the current
time and extract the hour use %@substr[%_time,0,2].
@upper[string] - returns the string shifted to upper case
4DOS Reference Manual Copyright 1991, JP Software Inc. 42
I/O Redirection
MS-DOS assumes input comes from the keyboard and output goes to
the display. The keyboard is referred to as the standard input,
and the display is referred to as the standard output. You can
change the default standard input and standard output by using
the < and > symbols on the command line. 4DOS also allows you to
redirect the standard error by appending the & character.
Normally, when redirecting standard output, if the specified file
doesn't exist, it is created; if it exists, it is overwritten,
and the previous contents are lost. If the variable NOCLOBBER is
set (see the SETDOS command in the Command Reference Guide), an
error message will be displayed if the file already exists.
For example, to get standard input from a file instead of the
keyboard, append:
< filename
to the command line. To redirect standard output to a file:
> filename
To redirect standard output to a file, overriding the NOCLOBBER
setting:
>! filename
To redirect standard output and standard error to a file:
>& filename
To redirect standard error only to a file:
>&> filename
To redirect standard output and standard error to a file,
overriding the NOCLOBBER setting:
>&! filename
To append standard output or standard error to a file, use >> in
place of the first >. If NOCLOBBER is set, the file must exist
before it can be appended to (unless overridden by a !).
Otherwise, 4DOS will create the file.
Pipes allow you to send the output of one command to the input of
another command by separating the commands with the vertical bar
(|). 4DOS will perform the commands in order from left to right.
4DOS Reference Manual Copyright 1991, JP Software Inc. 43
For example, to use the standard output of command1 as the
standard input of command2:
command1 | command2
To use the standard output and standard error of command1 as the
standard input of command2:
command1 |& command2
4DOS creates temporary files to hold the output of the pipes.
The default directory for these temporary files is the root
directory on the boot drive, but this can be overridden with the
TMP environment variable. This is useful when booting from a
floppy disk or a read-only network drive, or to speed up piping
operations by putting the temporary files on a RAM disk.
For example, to put the pipe files on a RAM disk defined as drive
E:
set tmp=e:\
4DOS also provides TEE and Y "pipe fittings" (see the Command
Reference Guide for more information on TEE and Y).
4DOS Reference Manual Copyright 1991, JP Software Inc. 44
Command Parsing
Because of the number of features in 4DOS, the command line
parsing is somewhat complex. The following is a summary of the
process 4DOS uses to interpret command line input:
∙ Read the command line (from console or batch file) and strip
leading white space
∙ Check for a leading @
∙ Save line to history list if no @ found, and if not in a
batch file
∙ Set the "no echo" flag if @ found
∙ Perform alias expansion, including expansion of nested
aliases, for the first command on the line.
∙ Perform environment variable expansion (except the EXCEPT,
FOR, GLOBAL, and SELECT commands) for the first command on
the line
∙ Scan the first command for pipes, compound commands or
conditionals
∙ Perform redirection (except the EXCEPT, FOR, GLOBAL, and
SELECT commands)
∙ Get the first argument and search for commands in the
following order:
1. Internal commands
2. External commands - .COM, .EXE, .BTM, and .BAT in that
order
3. Executable extensions (in the order they appear in the
environment)
∙ Execute the command
∙ Get the remainder of the command line, if any, and test for
conditionals
∙ Repeat the above steps for the next command on the line (if
any)
If you are having trouble getting aliases, batch files, multiple
commands, environment variable substitution, or other features
related to command parsing to work properly, you may want to step
through the command to determine how 4DOS is parsing it. When
doing this you may find it useful to run the command with ECHO
set on so you can see the expanded command 4DOS is trying to
execute.
4DOS Reference Manual Copyright 1991, JP Software Inc. 45
Command Reference Guide
4DOS has more than 70 internal commands. Some are the same as,
or improvements of, those in COMMAND.COM. The remainder are new
commands.
These commands are equivalent to those in COMMAND.COM:
BREAK CHCP CTTY DATE
EXIT GOTO TIME VER
VERIFY
These commands are enhanced:
CD CHDIR CLS COPY
DEL DIR ECHO ERASE
FOR IF MD MKDIR
PATH PAUSE PROMPT RD
REM REN RENAME RMDIR
SET SHIFT TYPE VOL
These commands are new:
? ALIAS ATTRIB BEEP
CALL CANCEL CDD COLOR
DESCRIBE DIRS DRAWBOX DRAWHLINE
DRAWVLINE ENDLOCAL ESET EXCEPT
FREE GLOBAL GOSUB HISTORY
IFF INKEY INPUT KEYSTACK
LIST LOG MEMORY MOVE
POPD PUSHD QUIT RETURN
SCREEN SCRPUT SELECT SETDOS
SETLOCAL SWAPPING TEE TEXT
TIMER UNALIAS UNSET Y
4DOS Reference Manual Copyright 1991, JP Software Inc. 46
Command Syntax
Words in uppercase are keywords and must be entered. Words in
lowercase are either options (e.g., "on", "off", "bright",
"blink") or variables (e.g. "filename", "path").
The expression d: represents a disk drive specification. (This
can be A:, B:, C:, etc.).
Words or letters in brackets ([ ]) are optional and are not
required to be entered.
A vertical bar (|) separating words means enter one word or the
other, but not both.
A letter preceded by a forward slash (/) is a switch. Switches
are used to enable or disable the various command options.
Because 4DOS supports multiple arguments for most commands,
switches affect specific arguments, and must be placed with those
arguments. Pay careful attention to switch placement as it is
described under the various commands. The effects occasionally
vary between commands in order to retain compatibility with
COMMAND.COM.
An ellipsis (...) means additional arguments are allowed, but not
required.
In the examples in the printed manual, characters in bold type
represent input from the user. Characters in normal type
represent 4DOS prompts or responses.
4DOS Reference Manual Copyright 1991, JP Software Inc. 47
?
Syntax: ?
Purpose: Display the 4DOS commands.
Comments: ? will display the 4DOS internal commands. For help
with the internal 4DOS and external DOS commands, see
the HELP command.
Example: Display the internal commands:
c:\> ?
? ALIAS ATTRIB BEEP
BREAK CALL CANCEL CD
CDD CHCP CHDIR CLS
COLOR COPY CTTY DATE
DEL DESCRIBE DIR DIRS
DRAWBOX DRAWHLINE DRAWVLINE ECHO
ENDLOCAL ERASE ESET EXCEPT
EXIT FOR FREE GLOBAL
GOSUB GOTO HISTORY IF
IFF INKEY INPUT KEYSTACK
LIST LOG MD MEMORY
MKDIR MOVE PATH PAUSE
POPD PROMPT PUSHD QUIT
RD REM REN RENAME
RETURN RMDIR SCREEN SCRPUT
SELECT SET SETDOS SETLOCAL
SHIFT SWAPPING TEE TEXT
TIME TIMER TYPE UNALIAS
UNSET VER VERIFY VOL
Y
4DOS Reference Manual Copyright 1991, JP Software Inc. 48
ALIAS
Syntax: ALIAS [/P] [/R filename...] [name[=][value]]
Purpose: Load or display the alias list, or define name as a
substitute for value.
Comments: Aliases are useful as a means of executing a complex
series of commands with a few keystrokes. Aliases can
also be used as "in memory batch files," and will run much
faster than disk-based batch files.
If you only specify name, ALIAS displays the current
alias value for name. Otherwise, ALIAS assigns the
command(s) in value to name. (Value may contain
environment variables or additional aliases.) Name can
now be used as if it were a built-in or external command.
If you don't specify any arguments, ALIAS displays the
current alias list.
Name is limited to no more than 80 characters, and
value to no more than 255 characters.
The /P(ause) option will pause after displaying each
page and wait for a key to be pressed.
The /R(ead) option allows you to load an alias list
from a file. This is much faster than loading aliases
from a batch file. The file is in the same format as the
ALIAS display, so ALIAS /R can accept as input a file
generated by redirecting ALIAS output. You can add
comments to an alias file by starting the comment line
with a colon (:). You can load multiple files with
one ALIAS /R command by placing the names one after
another on the command line, separated by spaces.
For example, the following commands will save the
aliases to a file, and then reload them from that file:
alias > alist
alias /r alist
When defining aliases at the command line, back quotes
must be used around the alias arguments that contain
multiple commands or variable references (%1, %&2, etc.)
to prevent premature expansion. Back quotes should NOT be
used when defining aliases in a file to be read with ALIAS
/R.
4DOS Reference Manual Copyright 1991, JP Software Inc. 49
Aliases may be nested; i.e., an alias can refer to another
alias, but they cannot refer back to themselves (a=b=a).
You can stop further alias expansion by prefacing the
alias argument with an asterisk (*). This also allows an
alias to refer to a command of the same name (see below
for an example).
An alias name can be truncated by including an asterisk
(*) in the alias name (see example).
To remove an alias, use the UNALIAS command.
For more information on aliases (including the use of
variables), see the Aliases section in Using 4DOS, and the
sample file ALIASES, distributed with 4DOS.
Example: Define D as an alias for DIR /AP:
c:\> alias d dir /ap
Display the current alias(es):
c:\> alias
D=dir /ap
The following example creates a new command WHEREIS
that searches a disk for matching files and
subdirectories:
c:\> alias whereis dir /dp
The same command using alias name truncation (this
alias can be referenced as wher, where, wherei, or
whereis):
c:\> alias wher*eis dir /dp
The following example erases the backup files, and then
displays the directory (the back-quotes are necessary to
prevent 4DOS from processing the command separator ^):
c:\> alias zap `del *.bak ^ dir /w`
4DOS Reference Manual Copyright 1991, JP Software Inc. 50
Redefine the 4DOS DIR command as a variation of itself
(wide display, including hidden and system files, pausing
after each page):
c:\> alias dir *dir /whp
Rename the 4DOS LIST command to DISPLAY, and alias LIST
to an external program:
c:\> alias display *list
c:\> alias list c:\util\list.com
The following examples show the use of alias arguments:
c:\> alias zap `erase %& ^ chkdsk ^ dir /w`
c:\> zap *.bak *.lst
This expands to:
erase *.bak *.lst ^ chkdsk ^ dir /w
c:\> alias reverse `echo %5 %4 %3 %2 %1`
c:\> reverse one two three four five
This expands to:
echo five four three two one
The following example shows the use of IFF inside an
alias. The alias modifies the SET command so that if SET
is entered with no arguments, it is replaced by a SET /P
(pause after displaying each page). Note the use of
asterisks (*set) to prevent alias loops (this should be
entered on one line):
c:\> alias set `iff "%1"=="" then *set /p^
else *set %&^endiff`
4DOS Reference Manual Copyright 1991, JP Software Inc. 51
ATTRIB
Syntax: ATTRIB [/D] [-|+[AHRS]] [d:][path]filename...
Purpose: Change the file or subdirectory attributes.
Comments: ATTRIB normally only modifies file attributes.
Specifying the /D(irectory) option will also modify
subdirectory attributes.
+A Set the archive attribute
-A Clear the archive attribute
+H Set the hidden attribute
-H Clear the hidden attribute
+R Set the read-only attribute
-R Clear the read-only attribute
+S Set the system file attribute
-S Clear the system file attribute
4DOS will preserve the previous file attributes and
change only the specified attributes. New attribute
values are allowed between filenames; otherwise ATTRIB
uses the same attributes specified for the previous
file(s). You cannot modify the directory or volume label
attributes.
You can display the file and subdirectory attributes
using the /A option in DIR.
Example: Set the read-only and hidden attributes for the file
MEMO:
c:\> attrib +rh memo
Set the archive attribute (file has been modified) for
MEMO, and change TEST.COM to system and not modified:
c:\> attrib +a memo +s -a test.com
4DOS Reference Manual Copyright 1991, JP Software Inc. 52
BEEP
Syntax: BEEP [frequency duration ...]
Purpose: Beep the speaker.
Comments: BEEP is normally used in batch files to signal that an
operation has been completed, or that the computer needs
attention (for example, to change disks). Because BEEP
allows you to specify the frequency and duration, you can
use it to play simple music. You can specify multiple
frequency/duration pairs on the command line.
The frequency is specified in Hertz, and the duration
in 1/18th second intervals. No sound will be generated
for frequencies less than 20 Hz, allowing you to insert
short delays. The default value for frequency is 440 Hz;
the default value for duration is 2.
The following table gives the frequency values for a
five octave range (middle C is 523 Hz):
_______________________________________________________
| | | | | | | |
| C | 65 | 131 | 262 | 523 | 1040 | 2093 |
|-------|-------|-------|-------|-------|-------|-------|
| C#/Db | 69 | 139 | 277 | 554 | 1103 | 2217 |
|-------|-------|-------|-------|-------|-------|-------|
| D | 73 | 147 | 294 | 587 | 1176 | 2349 |
|-------|-------|-------|-------|-------|-------|-------|
| D#/Eb | 78 | 156 | 311 | 622 | 1241 | 2489 |
|-------|-------|-------|-------|-------|-------|-------|
| E | 82 | 165 | 330 | 659 | 1311 | 2637 |
|-------|-------|-------|-------|-------|-------|-------|
| F | 87 | 175 | 349 | 698 | 1391 | 2794 |
|-------|-------|-------|-------|-------|-------|-------|
| F#/Gb | 93 | 185 | 370 | 740 | 1488 | 2960 |
|-------|-------|-------|-------|-------|-------|-------|
| G | 98 | 196 | 392 | 784 | 1568 | 3136 |
|-------|-------|-------|-------|-------|-------|-------|
| G#/Ab | 104 | 208 | 415 | 831 | 1662 | 3322 |
|-------|-------|-------|-------|-------|-------|-------|
| A | 110 | 220 | 440 | 880 | 1760 | 3520 |
|-------|-------|-------|-------|-------|-------|-------|
| A#/Bb | 117 | 233 | 466 | 932 | 1866 | 3729 |
|-------|-------|-------|-------|------ |-------|-------|
| B | 123 | 248 | 494 | 988 | 1973 | 3951 |
|_______|_______|_______|_______|_______|_______|_______|
Example: The following batch file fragment runs the program
DEMO, plays a few notes, and waits for you to press a key:
demo
beep 440 4 600 2 1040 6
pause Finished with the demo - hit a key...
4DOS Reference Manual Copyright 1991, JP Software Inc. 53
BREAK
Syntax: BREAK [on | off]
Purpose: Display, enable, or disable ^C / ^BREAK checking.
Comments: BREAK turns the ^C / ^BREAK checking on or off. If no
argument is given, it displays the current BREAK status.
If BREAK is off, MS-DOS will only check for a ^C during
DOS character I/O (screen, keyboard, serial port, or
printer operations). Many programs don't use these I/O
functions, and it can be difficult to break out of the
program with BREAK off. If BREAK is on, MS-DOS will check
for a ^C or ^BREAK during any MS-DOS operation (including
disk I/O).
BREAK defaults to OFF. You can change the default
BREAK setting by adding the following line to your
CONFIG.SYS file:
break=on
Example: Check the current BREAK status:
c:\> break
BREAK is OFF
Enable ^C checking in all MS-DOS calls:
c:\> break on
4DOS Reference Manual Copyright 1991, JP Software Inc. 54
CALL
Syntax: CALL [d:][path]filename
Purpose: Call a secondary batch file.
Comments: CALL allows batch files to call other batch files
(batch file nesting) without invoking a secondary copy of
the command processor. 4DOS supports batch file nesting
up to four levels deep. The calling batch file is
suspended while the called batch file runs. When the
called batch file finishes, the calling batch file resumes
execution at the next command. If you execute a batch
file from another batch file without using CALL, the first
batch file is terminated before the second one starts.
The current ECHO state will be inherited by a called
batch file.
See also CANCEL and QUIT.
Example: The following batch file fragment compares an input
line to "wp" and calls a secondary batch file if it
matches:
input Enter your choice: %%option
if "%option" == "wp" call wp.bat
4DOS Reference Manual Copyright 1991, JP Software Inc. 55
CANCEL
Syntax: CANCEL
Purpose: Terminate batch file processing.
Comments: The CANCEL command will end all batch file processing,
regardless of the batch nesting level. (Use QUIT to end a
nested batch file and return to the previous batch file.)
You can CANCEL at any point in a batch file.
See also CALL and QUIT.
Example: The following batch file fragment compares an input
line to "end" and terminates all batch file processing if
it matches:
input Enter your choice: %%option
if "%option" == "end" cancel
4DOS Reference Manual Copyright 1991, JP Software Inc. 56
CD / CHDIR
Syntax: CD [d:][pathname]
or
CHDIR [d:][pathname]
Purpose: Display or change the current directory.
Comments: Entering CD with no argument or only a disk drive name
will display the current directory. Entering CD and a
pathname will change the current directory.
Every disk drive on the system has its own current
directory. Specifying both a drive and a directory in the
CD command will change the current directory on the
specified drive, but will not change the default drive.
Use CDD to change both the drive and directory.
To start at the root directory, start the pathname with
a backslash (\). To start at the parent directory, start
the pathname with two periods (..). All other pathnames
start at the current directory.
MS-DOS will not accept directory names longer than 64
characters.
See also CDD.
Example: Change to the subdirectory C:\FINANCE\MYFILES:
c:\> cd \finance\myfiles
c:\finance\myfiles>
Change the default directory on drive A:
c:\> cd a:\utility
4DOS Reference Manual Copyright 1991, JP Software Inc. 57
CDD
Syntax: CDD [d:]pathname
Purpose: Change the current disk drive and directory.
Comments: CDD is similar to CD, except it also changes the
default disk drive.
To start at the root directory, start the pathname with
a backslash (\). To start at the parent directory, start
the pathname with two periods (..). All other pathnames
start at the current directory.
MS-DOS will not accept directory names longer than 64
characters.
See also CD.
Example: Change from the root directory on drive A to the
subdirectory C:\WP:
a:\> cdd c:\wp
c:\wp>
4DOS Reference Manual Copyright 1991, JP Software Inc. 58
CHCP
Syntax: CHCP [n]
Purpose: Display or change the current system code page.
Comments: Code page switching allows you to select different
character sets for language support. To use code page
switching, you must have an EGA or VGA display, and MS-DOS
3.3 or above.
Before using CHCP, you must first load the device
drivers (in CONFIG.SYS); make sure the information file
(COUNTRY.SYS) is available; load national language support
(using the NLSFUNC command); and prepare the specified
code page for the devices (using the MODE command with the
CODEPAGE PREPARE option).
CHCP accepts one of the two prepared system code pages.
An error message is displayed if a code page is selected
that has not been prepared for the system.
Entering CHCP with no arguments displays the active
code page.
See your MS-DOS manual for more information on CHCP.
Example: Display the current code page:
c:\> chcp
Active code page: 437
Set the code page to multilingual:
c:\> chcp 850
4DOS Reference Manual Copyright 1991, JP Software Inc. 59
CLS
Syntax: CLS [[bright] [blink] fg ON bg]
Purpose: Clear the video display, optionally to the specified
colors.
Comments: CLS clears the display and moves the cursor to the
upper left corner. fg is the foreground color, bg the
background color. Only the first three characters of the
color name and attributes ("bright" and "blink") are
required.
You must have ANSI.SYS (or another ANSI compatible
screen driver) loaded to set screen colors.
The available colors are:
Black Blue Green Red
Magenta Cyan Yellow White
CLS is normally used in batch files to clear the screen
before displaying text.
See also COLOR.
Example: Clear the display:
c:\> cls
Clear the display to a blue background, and set white
characters as the new default:
c:\> cls white on blue
4DOS Reference Manual Copyright 1991, JP Software Inc. 60
COLOR
Syntax: COLOR [bright] [blink] fg ON bg
Purpose: Set the screen display colors.
Comments: fg is the foreground color, bg the background color.
Only the first three characters of the color name and
attributes ("bright" and "blink") are required
You must have ANSI.SYS (or another ANSI compatible
screen driver) loaded to set screen colors.
The available colors are:
Black Blue Green Red
Magenta Cyan Yellow White
See also CLS and SCRPUT.
Example: Set the default screen colors to bright white text on a
blue background:
c:\> color bright white on blue
4DOS Reference Manual Copyright 1991, JP Software Inc. 61
COPY
Syntax: COPY [/MPQRUV] [d:][path]filename[+]...[/AB]
[[d:][path]filename][/AB]
Purpose: Copy or append one or more files.
Comments: Unlike COMMAND.COM, 4DOS allows you to copy several
unrelated files to a target directory with a single COPY
command. If there are two or more arguments on the
command line, COPY assumes the last argument is the
target. If there is only one argument, the target is
assumed to be the current directory.
The plus (+) tells 4DOS to append two or more files to
a single target file. If you don't specify a target, COPY
will append each subsequent file to the first file.
If you specify more than one source file, and the
target is NOT a directory, COPY will automatically append
the files to the target.
The /A(SCII) and /B(inary) options apply to the
preceding filename and to all subsequent filenames on the
command line until another /A or /B is entered. The other
options (/M, /P, /Q, /R, /U, /V) apply to all filenames on
the command line.
If you use the /A option with a source filename, 4DOS
will copy the file up to, but not including, the first ^Z
character in the file. If you use /A with a target
filename, 4DOS will add a ^Z to the end of the file. 4DOS
defaults to /A when appending files, or when the source or
target is a device.
If you use the /B option with a source filename, 4DOS
will copy the entire file. Using /B with a target
filename prevents 4DOS from adding a ^Z to the end of the
target file. 4DOS defaults to /B for normal file copies.
The /M(odified) option copies only those files with the
archive bit set (see ATTRIB). The archive bit will NOT be
cleared after copying.
The /P(rompt) option prompts you to confirm each file
copy (Y or N). An N response will skip that particular
source file.
4DOS Reference Manual Copyright 1991, JP Software Inc. 62
The /Q(uiet) option turns off the display of the files
copied.
The /R(eplace) option prompts before overwriting an
existing file.
The /U(pdate) option copies only those source files
that are newer than a matching target file, or where a
matching target file doesn't exist.
The /V(erify) option verifies each disk write. This is
the same as executing the VERIFY ON command, but is only
active during the COPY command.
See also MOVE.
Example: Copy the files MEMO1, PROJECT8.WKS, and UPDATE.BAT to
the root directory on drive A:
c:\> copy memo1 project8.wks update.bat a:\
Append the files MEMO1, MEMO2, and MEMO3, and store the
result in BIGMEMO:
c:\> copy memo1+memo2+memo3 bigmemo
Copy only those files in the root directory on drive A
that are newer than the matching files in the current
directory, or which don't exist in the current directory:
c:\> copy /u a:\*.* c:\*.*
Copy files from the root directory on drive A to the
current directory, but prompt before overwriting existing
files:
c:\> copy /r a:\*.*
Copy a downloadable font file to the printer in binary
mode:
c:\> copy myfont.dat prn: /b
4DOS Reference Manual Copyright 1991, JP Software Inc. 63
CTTY
Syntax: CTTY device
Purpose: Change the default console device.
Comments: At startup, 4DOS uses the keyboard as the standard
input device and the display as the standard output
device. CTTY allows you to change the console (CON:) to
another device that can perform standard character I/O.
CTTY works only for those programs that use the
standard MS-DOS I/O functions (this includes all of the
4DOS internal commands with the exception of DRAWBOX,
DRAWHLINE, DRAWVLINE, LIST, SCREEN, SCRPUT, and SELECT).
Example: Change the console to the first serial port:
c:\> ctty com1:
Change the console back to the standard keyboard and
display:
c:\> ctty con:
4DOS Reference Manual Copyright 1991, JP Software Inc. 64
DATE
Syntax: DATE [mm-dd-yy]
Purpose: Display and (optionally) change the system date.
Comments: If you don't enter any parameters, DATE will display
the current system date and time, and prompt for the new
date. Press ENTER if you don't wish to change the date,
otherwise enter the new date.
The parameters for the DATE command are:
mm (month) = 1 - 12
dd (day) = 1 - 31
yy (year) = 00 - 99 or 1900 - 2099
You can use hyphens, slashes, or periods to separate
the month, day, and year entries. If you enter only two
digits for the year and it is below 80 4DOS will assume
it is in the 21st century; if it is 80 or above 4DOS will
assume it is in the 20th century. You can specify the
year you want explicitly by using a 4-digit value.
The format for the date entry depends on the country
code defined in the CONFIG.SYS file or by the CHCP
command. The default format is U.S. (mm-dd-yy). The
European format is dd-mm-yy; the Japanese is yy-mm-dd.
See also CHCP and TIME.
Example: Enter the date from the command line:
c:\> date 12/25/89
To be prompted for the date:
c:\> date
Mon Dec 25, 1989 9:30:06
Enter new date (mm-dd-yy):
4DOS Reference Manual Copyright 1991, JP Software Inc. 65
DEL / ERASE
Syntax: DEL [/PQY] [d:][path]filename...
or
ERASE [/PQY] [d:][path]filename...
Purpose: Erase the specified file(s) from the disk.
Comments: If the /P(rompt) option is specified, 4DOS will prompt
you to enter a Y or N to confirm file deletions for all
filenames.
The /Q(uiet) option turns off the display of the files
deleted.
The /Y(es) option is the reverse of /P - it assumes a Y
response to everything, including deleting an entire
subdirectory (*.*). Use this option with caution!
If you enter a subdirectory name, or a filename
composed only of wildcards (* and/or ?), DEL asks for
confirmation (Y or N), unless you specified the /Y(es)
option. If you respond with a Y, DEL will delete all the
files in that subdirectory (except hidden, system, and
read-only files).
Example: Erase all the files in the current directory with a
.BAK or .PRN extension:
c:\> del *.bak *.prn
Confirm the deletion of all files in the current
directory with .WKS extensions:
c:\> del /P *.wks
Delete JAN89.WKS (Y/N)? n
Delete FEB88.WKS (Y/N)? y
Delete DEC88.WKS (Y/N)? y
4DOS Reference Manual Copyright 1991, JP Software Inc. 66
DELAY
Syntax: DELAY [seconds]
Purpose: Pause for a specified length of time.
Comments: DELAY is useful in batch file loops while waiting for a
condition to occur. The default value is one second.
You can cancel a DELAY loop by pressing ^C.
Example: Wait for 10 seconds:
delay 10
4DOS Reference Manual Copyright 1991, JP Software Inc. 67
DESCRIBE
Syntax: DESCRIBE [d:][path]filename ["description"] ...
Purpose: Create, modify, or delete file and subdirectory
descriptions.
Comments: DESCRIBE adds descriptions (up to 40 characters) to MS-
DOS filenames and subdirectories. The descriptions will
be displayed when using DIR with the default single column
option, or when using SELECT.
File descriptions allow you to identify your files in
much more meaningful ways than MS-DOS allows in an eight
character filename.
You can enter a description on the command line by
entering the filename followed by the description enclosed
in quotes. Using wildcards (* and ?) and/or multiple
filenames with a description on the command line will give
all matching files the same description.
Descriptions are stored in each directory in a hidden
file called DESCRIPT.ION. Use the ATTRIB command to
"unhide" this file if you need to copy or delete it.
The description file is modified appropriately whenever
you perform an internal command (such as COPY, MOVE, DEL,
or RENAME), but not if you use an external program (such
as XCOPY or a shell program).
Example: Create a description for the file MEMO.TXT:
c:\> describe memo.txt
Describe "memo.txt" : Memo to Bob about party
Enter the same description from the command line:
c:\> describe memo.txt "Memo to Bob about party"
4DOS Reference Manual Copyright 1991, JP Software Inc. 68
DIR
Syntax: DIR [/124ACDFHJNOeirtuzPQSVWX] [[d:][path]filename[+]...]
Purpose: Display information about files and subdirectories.
Comments: DIR displays information about the files and
subdirectories in the specified directory. Depending upon
the options specified, DIR can show the filename, file
attributes, size, date and time of the most recent change
to the file, and the file description.
DIR allows wildcard characters (* and ?) in the
filename. If you don't specify a filename, DIR defaults
to *.* (display all files and subdirectories in the
current directory).
If you append filenames with a +, 4DOS will display the
matching filenames in a single directory listing.
If a country code was defined in the CONFIG.SYS file or
by the CHCP command, DIR will display the date in the
format for that country. The default date format is U.S.
(mm-dd-yy).
DIR can handle directories of any size, limited only by
the available memory. Each filename requires 32 bytes of
DOS memory plus the size of the description (if any); a
system with 128K of free DOS memory can display up to
4,000 files per directory.
Options on the command line apply only to the filenames
which follow the option, except that options at the end of
the line apply to the preceding filename only. This
allows you to specify several options for a group of
files, and retains compatibility with COMMAND.COM when a
single filename is specified.
The DIR options are:
1 Single column display - display the filename, size,
date, time, and description. This is the default.
2 Two column display - display the filename, size,
date, and time.
4 Four column display - display the filename and size
(in K(ilobytes) or M(egabytes).
4DOS Reference Manual Copyright 1991, JP Software Inc. 69
A Display filenames and attributes (see ATTRIB), in
the format RHSA, where:
R Read-only
H Hidden
S System
A Archive
When displaying attributes, DIR cannot also
display file descriptions.
C Display filenames in upper case (like COMMAND.COM).
See also SETDOS /U.
D Display contents of the current directory and all of
its subdirectories. DIR will only display headers
and summaries for those directories with matching
filenames.
F Display files only (no subdirectories).
H Display all files, including hidden and system
files.
J Justify filenames (same format as COMMAND.COM).
N Reset DIR options to the default values (useful when
displaying some files in one format, and then
changing back to the default format).
O? Sort sequence, where ? can be any combination of the
following options:
e Sort by extension
i Sort by the file description (see
DESCRIBE)
r Reverse the normal sort order
t Sort by time (oldest first)
u Unsorted (same as COMMAND.COM)
z Sort by size
The default sort is by filename.
P Pause after each screen page and wait for a key to
be pressed (useful for displaying long directory
listings).
Q Suppress header line and summaries, and display file
or subdirectory names only, in a single column
(useful when redirecting output to a file or
another program).
S Display summary only (number of files & bytes used).
V Display filenames sorted vertically rather than
horizontally (with the /2, /4, or /W option).
W Wide display - display the filenames only,
horizontally across the screen (5 columns on an
80-character display).
X Display subdirectories only.
See also DESCRIBE and SELECT.
4DOS Reference Manual Copyright 1991, JP Software Inc. 70
Example: Display the .WKS files, and then the .WK1 files in the
current directory:
c:\> dir *.wks *.wk1
Display the .WKS and .WK1 files together:
c:\> dir *.wks+*.wk1
Display all the files on drive C, including hidden and
system files, pausing after each page:
c:\> dir /dhp c:\*.*
4DOS Reference Manual Copyright 1991, JP Software Inc. 71
DIRS
Syntax: DIRS
Purpose: Display the current directory stack.
Comments: DIRS displays the directory stack used by PUSHD and
POPD (most recent entries first). The directory stack
holds up to 255 characters (about 10 to 20 entries).
See also PUSHD and POPD.
Example: Change directories and then display the directory
stack:
c:\> pushd c:\database
c:\database> pushd d:\wordp\memos
d:\wordp\memos> dirs
c:\database
c:\
4DOS Reference Manual Copyright 1991, JP Software Inc. 72
DRAWBOX
Syntax: DRAWBOX ulrow ulcol lrrow lrcol style [bright] [blink] fg
ON bg [FILL bgfill]
Purpose: Draw a box on the screen.
Comments: DRAWBOX is useful for creating attractive screen
displays in batch files. DRAWBOX detects other lines and
boxes on the display, and creates the appropriate
connector characters when possible (not all types of lines
can be connected with the available characters).
The row and column are zero-based, so on a standard 25
line by 80 column display, valid rows are 0 - 24 and valid
columns are 0 - 79.
The parameters are:
ulrow Row for upper left corner
ulcol Column for upper left corner
lrrow Row for lower right corner
lrcol Column for lower right corner
style Box drawing style:
0 - borderless
1 - single line
2 - double line
3 - single line on top and bottom,
double on sides
4 - double line on top and bottom,
single on sides
fg Foreground character color
bg Background character color
bgfill Background fill color (for the inside of the
box)
Only the first three characters of the color name and
attributes ("bright" and "blink") are required. The
available colors are:
Black Blue Green Red
Magenta Cyan Yellow White
See also DRAWHLINE and DRAWVLINE.
Example: Draw a single line box around the entire screen with
bright white lines on a blue background:
drawbox 0 0 24 79 1 bright white on blue fill blue
4DOS Reference Manual Copyright 1991, JP Software Inc. 73
DRAWHLINE
Syntax: DRAWHLINE row column len style [bright] [blink] fg ON bg
Purpose: Draw a horizontal line on the screen.
Comments: DRAWHLINE is useful for creating attractive screen
displays in batch files. DRAWHLINE detects other lines
and boxes on the display, and creates the appropriate
connector characters when possible (not all types of lines
can be connected with the available characters).
The row and column are zero-based, so on a standard 25
line by 80 column display, valid rows are 0 - 24 and valid
columns are 0 - 79.
The parameters are:
row Start row
column Start column
len Length of line
style Line drawing style:
1 - single line
2 - double line
fg Foreground character color
bg Background character color
Only the first three characters of the color name and
attributes ("bright" and "blink") are required. The
available colors are:
Black Blue Green Red
Magenta Cyan Yellow White
See also DRAWBOX and DRAWVLINE.
Example: Draw a double line along the top row of the display
with green characters on a blue background:
drawhline 0 0 79 2 green on blue
4DOS Reference Manual Copyright 1991, JP Software Inc. 74
DRAWVLINE
Syntax: DRAWVLINE row column len style [bright][blink] fg ON bg
Purpose: Draw a vertical line on the screen.
Comments: DRAWVLINE is useful for creating attractive screen
displays in batch files. DRAWVLINE detects other lines
and boxes on the display, and creates the appropriate
connector characters when possible (not all types of lines
can be connected with the available characters).
The row and column are zero-based, so on a standard 25
line by 80 column display, valid rows are 0 - 24 and valid
columns are 0 - 79.
The parameters are:
row Start row
column Start column
len Length of line
style Line drawing style:
1 - single line
2 - double line
fg Foreground character color
bg Background character color
Only the first three characters of the color name and
attributes ("bright" and "blink") are required. The
available colors are:
Black Blue Green Red
Magenta Cyan Yellow White
See also DRAWBOX and DRAWHLINE.
Example: Draw a double width line along the left margin of the
display with bright red characters on a black background:
drawvline 0 0 24 2 bright red on black
4DOS Reference Manual Copyright 1991, JP Software Inc. 75
ECHO
Syntax: ECHO [on | off | message]
Purpose: Display the echo status, enable or disable batch file
or command line echoing, or display a message.
Comments: 4DOS defaults to ECHO ON in batch files. To prevent a
line from being echoed, preface it with the @ symbol. You
can default to ECHO OFF by setting the variable VERBOSE to
0 (see SETDOS). The current ECHO state is inherited by
called batch files.
4DOS defaults to ECHO OFF during keyboard input. If
you set ECHO ON from the command line, 4DOS will display
the fully parsed and expanded commands (including aliases
and variables) before they are executed. The keyboard
ECHO state is independent of the batch file ECHO state;
changing ECHO in a batch file has no effect on the display
at the command prompt, and vice versa.
If no arguments are entered, ECHO displays the current
echo status (ON or OFF).
ECHO commands in a batch file will send messages to the
screen while the batch file executes, even if ECHO is set
OFF. You cannot use the command separator character or
the 4DOS redirection symbols (| > <) in an ECHO message,
unless you enclose them in quotes or precede them with the
escape character.
See also SCREEN, SCRPUT, SETDOS and TEXT.
Example: Enable command line echoing:
c:\> echo on
Display a message in a batch file:
echo Processing your print files...
Turn off batch file echoing, without displaying ECHO
itself:
@echo off
4DOS Reference Manual Copyright 1991, JP Software Inc. 76
ENDLOCAL
Syntax: ENDLOCAL
Purpose: Restore the saved disk drive, directory, environment
variables and aliases.
Comment: ENDLOCAL restores the disk drive, directory,
environment variables and aliases saved by the previous
SETLOCAL command. SETLOCAL and ENDLOCAL can only be used
in batch files, not in aliases.
See also SETLOCAL.
Example: This batch file fragment saves the drive, current
working directory, environment variables and aliases,
changes the drive and directory, modifies some environment
variables, runs the program TEST1, and then restores the
original values:
setlocal
cdd d:\test
set path=c:\;c:\dos;c:\util
set lib=d:\lib
test1
endlocal
4DOS Reference Manual Copyright 1991, JP Software Inc. 77
ESET
Syntax: ESET varname...
Purpose: Edit environment variables and/or aliases.
Comments: ESET allows you to edit your environment variables and
aliases using the 4DOS line editing commands (see Command
Line Editing in Using 4DOS). The cursor will be
positioned at the first character of the variable or
alias.
ESET will search for environment variables first, and
then aliases. If you have an environment variable and an
alias with the same name (a bad idea!), ESET will only be
able to edit the environment variable.
4DOS limits environment variable and alias names to 80
characters, and their arguments to 255 characters.
See also ALIAS, UNALIAS, SET, and UNSET.
Example: Edit the MS-DOS executable file search path:
c:\> eset path
path=c:\;c:\dos;c:\util
Create and then edit an alias:
c:\> alias d dir /djp
c:\> eset d
d=dir /djp
4DOS Reference Manual Copyright 1991, JP Software Inc. 78
EXCEPT
Syntax: EXCEPT ([d:][path]filename...) command [args...]
Purpose: Perform a command, except on the file(s) specified.
Comments: EXCEPT provides a means of executing a command on a
group of files and/or subdirectories, except those
enclosed within the parentheses.
The command can be a 4DOS internal command or alias, an
external command, or a batch file.
You may use the wildcard characters (? and *) in a
filename.
When using filename completion (see Command Line
Editing in Using 4DOS) to get the filenames inside the
parentheses, type a space after the open parenthesis
before entering a partial filename or pressing F9.
Otherwise the command line editor will treat the open
parenthesis as the first character of the filename to be
completed.
EXCEPT prevents operations on the specified file(s) by
setting the hidden attribute, performing the command, and
then clearing the hidden attribute. If EXCEPT is aborted
in an unusual way, you may need to use the ATTRIB command
to "unhide" (-H) the file(s).
EXCEPT will not work with programs or commands that
ignore the hidden attribute.
See also ATTRIB.
Example: Erase all the files in the current directory, except
those beginning with MEMO and those ending in .WKS:
c:\> except (memo*.* *.wks) erase *.*
Copy all the files and subdirectories except those in
C:\MSC and C:\DOS on drive C to drive D:
c:\> except (c:\msc c:\dos) xcopy c:\*.* d:\ /s
4DOS Reference Manual Copyright 1991, JP Software Inc. 79
EXIT
Syntax: EXIT [n]
Purpose: Return from a secondary command processor.
Comments: Some application programs will start a secondary copy
of the command processor to allow you to execute MS-DOS
commands. To return to the application again, type EXIT.
If you include a numeric value after the EXIT command, 4DOS
will return this value to the calling program as the error
level. If the value is not specified, the error level from
the most recently executed external program is returned.
If no external program has been executed, 0 is returned.
You cannot EXIT from the primary command processor.
Example: Return to the previous command processor or
application:
c:\> exit
4DOS Reference Manual Copyright 1991, JP Software Inc. 80
FOR
Syntax: FOR %var IN (set) [DO] command ...
Purpose: Repeat a command for several variables.
Comments: 4DOS sets var sequentially to each member of (set), and
then evaluates and executes command for every argument in
(set). If one of the arguments in (set) contains MS-DOS
wildcard characters (* and ?), var will be set
sequentially to each matching filename on the disk.
The command can be a 4DOS internal command or alias, an
external command, or a batch file.
In COMMAND.COM, you must use a single % for the
variable name from the command line, and %% when in a
batch file. 4DOS will accept either % or %% in either
case.
COMMAND.COM requires the variable name to be a single
character; 4DOS supports variable names up to 80
characters.
COMMAND.COM requires the word "DO" on the command line;
it is optional in 4DOS.
Note that 4DOS supports nested FOR statements;
COMMAND.COM does not.
Example: The following example compiles the C programs in the
current directory that have a 2 or a 3 somewhere in their
name:
c:\msc> for %a in ( *2*.c *3*.c ) do cl %a ;
The following example uses variable functions to delete
the .BAK files for which a corresponding .TXT file exists
in the current directory (this should be entered on one
line):
c:\docs> for %file in (*.txt) if exist
%@name[%file].bak del %@name[%file].bak
4DOS Reference Manual Copyright 1991, JP Software Inc. 81
FREE
Syntax: FREE [d:]...
Purpose: Display the total disk space, total bytes used, and
total bytes free on the specified (or default) drive(s).
Comments: FREE provides the same disk information as the external
MS-DOS command CHKDSK, but without the wait.
See also MEMORY.
Example: Display the status of the current drive:
c:\> free
Volume in drive C: is DEVELOPMENT
42,496,000 bytes total disk space
36,851,712 bytes used
5,644,288 bytes free
Display the status of drives A and C:
c:\> free a: c:
Volume in drive A: is unlabeled
1,213,952 bytes total disk space
1,115,136 bytes used
98,816 bytes free
Volume in drive C: is DEVELOPMENT
42,496,000 bytes total disk space
36,851,712 bytes used
5,644,288 bytes free
4DOS Reference Manual Copyright 1991, JP Software Inc. 82
GLOBAL
Syntax: GLOBAL [/IQ] command [args]
Purpose: Execute a command in the current directory and its
subdirectories.
Comments: GLOBAL performs the command first in the current
directory, and then in every subdirectory under the
current directory.
The command can be a 4DOS internal command or alias, an
external command, or a batch file.
GLOBAL will terminate if the command returns a non-zero
exit code, unless you specify the /I(gnore result) switch.
GLOBAL will display the current directory unless you specify
the /Q(uiet) switch.
Example: Erase all the files with a .BAK extension in every
directory on C:
c:\> global erase *.bak
Copy the files in every directory on drive A to the
directory C:\TEMP :
a:\> global copy *.* c:\temp
4DOS Reference Manual Copyright 1991, JP Software Inc. 83
GOSUB
Syntax: GOSUB label
Purpose: Call a subroutine in a batch file.
Comments: GOSUB calls the specified label as a subroutine. The
subroutine must end with a RETURN statement. After the
RETURN, 4DOS will continue processing with the command
following the GOSUB command.
If the label doesn't exist, the batch file is
terminated with the error message "Label not found."
The label must begin with a colon (:), and appear by
itself on the line. 4DOS ignores case differences when
matching labels.
See also GOTO and RETURN.
Example: The following batch file fragment calls a subroutine
which displays the directory and returns:
echo Calling a subroutine
gosub subr1
echo Returned from the subroutine
quit
:subr1
dir /hw
return
4DOS Reference Manual Copyright 1991, JP Software Inc. 84
GOTO
Syntax: GOTO label
Purpose: Continue batch file processing at the line following
the label.
Comments: GOTO changes the current position in the batch file to
the line immediately following the label. If the label
doesn't exist, the batch file is terminated with the error
message "Label not found."
The label must begin with a colon (:), and appear by
itself on the line. 4DOS ignores case differences when
matching labels.
To avoid errors in the processing of nested IFF statements,
GOTO cancels all active IFF statements. This means that to
avoid errors GOTOs inside IFF statements must branch
entirely outside all IFF blocks which are active at the time
of the GOTO.
See also GOSUB.
Example: The following batch file fragment checks for the
existence of the file CONFIG.SYS. If the file exists,
4DOS jumps to C_EXISTS and copies all the files from the
current directory to the root directory on A. If
CONFIG.SYS doesn't exist, 4DOS prints an error message and
exits.
if exist config.sys goto C_EXISTS
echo CONFIG.SYS doesn't exist - exiting.
quit
:C_EXISTS
copy *.* a:\
4DOS Reference Manual Copyright 1991, JP Software Inc. 85
HELP
Syntax: HELP [/BW] [/R] [topic]
Purpose: Provide help for 4DOS and MS-DOS commands.
Comments: The HELP command displays the proper syntax and a brief
description of 4DOS and MS-DOS commands. You can also
call HELP by pressing F1 at the 4DOS prompt.
If you enter HELP with no topic, HELP will display all
the commands it can help you with. Select a topic using
the cursor keys and press ENTER. For help on a specific
command, enter HELP followed by the command name.
The /BW switch forces HELP to monochrome mode on color
systems. The /R switch turns off dynamic window resizing
and forces all HELP screens to full screen size regardless
of the amount of text they contain. HELP switches may be
set permanently by setting the values in the 4HELPC
environment variable (e.g. SET 4HELPC=/BW).
Detailed information on how to use the HELP system is
provided with HELP itself. Once you have started HELP,
follow the instructions on the screen regarding the
effects of various keys.
HELP.EXE and DOS.HLP must be in the current directory or
one of the directories specified in the PATH environment
variable. If you change the name of HELP.EXE or keep the
help files in a directory which is not on your PATH, you
must store the full path and filename for the help program
in the 4HELP environment variable. To specify a text file
name other than DOS.HLP, store the full path and filename for
the help text file in the 4HELPF environment variable.
The HELPCFG program included with 4DOS allows you to
customize HELP's colors to suit your own preferences.
If you want to customize the help text (for example, to
add HELP for your own commands or aliases), you will need
the 4DOS Utility Disk (available from JP Software) which
contains the source text and hypertext compiler.
HELP is an external command.
Example: Display and select from all the available help topics:
c:\> help
For help on COPY:
c:\> help copy
4DOS Reference Manual Copyright 1991, JP Software Inc. 86
HISTORY
Syntax: HISTORY [/F] [/R [d:][path]filename]
Purpose: Display, clear, or read the history list.
Comments: If no parameters are entered, HISTORY will display the
current history list.
The /F(ree) option clears the command history list.
The /R(ead) option loads the command history from the
specified file. You can save the history list by
redirecting its output to a file.
The number of commands saved in the history list
depends on the length of each command line. The history
list size can be specified at startup from 512 to 8192
characters (see Installation). The default size is 1024
characters.
You can disable saving commands to the history list, or
specify a minimum command line length to save, with the
SETDOS /H command.
See also SETDOS.
Example: Display the history list:
c:\> history
Clear the history entries:
c:\> history /f
Save the history list to the file HISTFILE, and then
read it in again:
c:\> history > histfile
c:\> history /r histfile
4DOS Reference Manual Copyright 1991, JP Software Inc. 87
IF
Syntax: IF [NOT] condition command
Purpose: Allow conditional execution of commands.
Comments: 4DOS first tests the given condition. If the condition
is true, 4DOS executes the specified command, otherwise
the command will be ignored. If you use the NOT option,
the command is executed only when the condition is false.
IF statements can be nested.
The command can be a 4DOS internal command or alias, an
external command, or a batch file.
For the string tests, case differences are ignored. When
comparing strings, you should enclose the strings in double
quotes (see examples). If both arguments to be compared
begin with digits, IF will do a numeric comparison; otherwise
IF does an ASCII comparison.
The condition can be any of the following:
string1 == string2
string1 EQ string2
If string1 is equal to string2, the condition is
true.
string1 NE string2
If string1 is not equal to string2, the condition
is true.
string1 LT string2
If string1 is < string2, the condition is true.
string1 LE string2
If string1 is <= string2, the condition is true.
string1 GE string2
If string1 is >= string2, the condition is true.
string1 GT string2
If string1 is > string2, the condition is true.
In the tests below, the term "condition" refers to one of
the relational operators described above (==, NE, LT, etc.).
4DOS Reference Manual Copyright 1991, JP Software Inc. 88
ATTRIB [d:][path]filename [RHSVDA]
If the file has matching attributes, the condition
is true. See also ATTRIB and DIR. The attributes
are :
R Read-only
H Hidden
S System
V Volume
D Directory
A Archive
N No attributes set
For the volume name test the filename used must
refer to the root directory. Volume names longer
than 8 characters require a period after the eigth
character (e.g. IF ATTRIB A:\MYFILES0.107 V ...).
DISKFREE condition n[K | M]
Test for the free disk space on the current drive.
DOSMEM condition n[K]
Test for the free DOS memory.
EMS condition n[K | M]
Test for the amount of free expanded memory.
EXTENDED condition n[K | M]
Test for the amount of extended memory (non-XMS).
ERRORLEVEL [condition] n
Test the exit code of the preceding external
program. ERRORLEVEL supports the same conditions
as the string comparisons (for example, ==, LE,
etc.). If no condition is specified, the default
is GE. NOTE: Not all programs return an explicit
exit code. In those cases, the behavior of
ERRORLEVEL is undefined.
EXIST [d:][path]filename
If the file exists, the condition is true. You
can use wildcard characters (* and ?) in the
filename, in which case the condition is true if
any file matching the wildcards exists.
FILESIZE filename condition n[K | M]
Test for the size of the specified file.
ISALIAS aliasname
If the specified name is an alias, the condition
is true.
4DOS Reference Manual Copyright 1991, JP Software Inc. 89
ISDIR [d:]path
If the subdirectory exists, the condition is true.
MONITOR condition [MONO | COLOR]
Test for the monitor type (condition should be ==,
EQ, or NE).
VIDEO condition [MONO | CGA | EGA | VGA]
Test for the video card type (condition should be
==, EQ, or NE).
XMS condition n[K | M]
Test for the amount of available XMS 2.0 extended
memory.
The DOSFREE, EMS, EXTENDED, and XMS tests allow testing
either by bytes (default), kilobytes (by appending a K to
the test value), or megabytes (by appending an M).
See also IFF.
Example: Test for the presence of A:\JAN.DOC, and copy it to the
root directory on drive C if it exists:
c:\> if exist a:\jan.doc copy a:\jan.doc c:\
This batch file fragment tests for a string value:
input "Enter your selection : " %%cmd
if "%cmd" == "WP" goto wordproc
if "%cmd" NE "GRAPHICS" goto badentry
Test for more than 500K of free DOS memory:
c:\> if dosfree gt 500K echo More than 500K free
Test for expanded memory greater than 2 Mb:
c:\> if ems gt 2M echo More than 2 Mb EMS available
Run a program ("MONOPROG") if the monitor type is
monochrome:
c:\> if monitor==mono monoprog
This batch file fragment tests to see if the disk in
drive A is labeled "INSTALL1":
if attrib a:\install1 V goto INSTALL1
4DOS Reference Manual Copyright 1991, JP Software Inc. 90
IFF
Syntax: IFF [NOT] condition THEN ^ ... ^ ELSE[[IFF] ... THEN] ^
... ^ ENDIFF
Purpose: Allow IF/THEN/ELSE conditional execution of commands.
Comments: 4DOS first tests the given condition. If the condition
is true, 4DOS executes the specified command(s) until the
next ELSE, ELSEIFF, or ENDIFF, otherwise the command(s)
will be ignored and 4DOS will continue parsing at the next
ELSE, ELSEIFF, or ENDIFF. If you use the NOT option,
commands are executed only when the condition is false.
IFF statements can be nested up to 15 levels deep.
The command can be a 4DOS internal command or alias, an
external command, or a batch file.
See the IF command for a list of the tests available.
Example: The following batch file fragment tests the monitor
type (monochrome or color), and sets the appropriate
colors and prompt (the PROMPT commands should be entered
on one line):
iff monitor==color then
color bright white on blue ^ cls
prompt=$e[s$e[1;1f$e[41;1;37m$e[K Path:
$p$e[u$e[44;37m$n$g
else
prompt=$e[s$e[1;1f$e[0;7m$e[K Path:
$p$e[u$e[0m$n$g
endiff
The following alias checks to see if the argument is a
subdirectory. If so, the alias deletes the subdirectory's
files and removes it (enter this on one line):
c:\> alias zap `iff isdir %1 then ^ del %1 ^ rd %1 ^
else ^ echo Not a directory! ^ endiff`
4DOS Reference Manual Copyright 1991, JP Software Inc. 91
INKEY
Syntax: INKEY [/Wn] [text] %%varname
Purpose: Get a single keystroke environment variable from
standard input.
Comments: You can optionally display prompt text before the
variable name.
The /W(ait) option allows you to specify a timeout
period, where n is the number of seconds to wait for a
response. If no keystroke is entered by the end of the
timeout period, INKEY returns with the variable unchanged.
You can specify /W0 to check if a key is already in the
buffer, and return immediately.
ASCII values from 1 to 255 are stored as a character.
Extended characters (for example, function keys and cursor
keys) are stored as a string in decimal format, with a
leading @ (for example, the F1 key is @59). This is the
same format used by the KEYSTACK command. See Appendix C
for a list of the extended key codes.
INKEY and INPUT are normally used in batch files,
allowing you great flexibility in entering or changing
batch variables.
If you press ^C or ^BREAK while INKEY is waiting for a
key, execution of an alias will be terminated, and
execution of a batch file will be suspended while you are
prompted whether to cancel the batch job (see Batch Files
in Using 4DOS).
See also INPUT.
Example: The following batch file fragment prompts for a
character and stores it in the variable NUM:
inkey Enter a number from 1 to 9: %%num
The following batch file fragment waits up to 10
seconds for a character, then tests to see if a "Y" was
entered (the INKEY command should be entered on one line):
set net=N
inkey /w10 Do you want to load the network (Y/N)?
%%net
if "%net" == "Y" goto load_net
4DOS Reference Manual Copyright 1991, JP Software Inc. 92
INPUT
Syntax: INPUT [/Wn] [text] %%varname
Purpose: Enter an environment variable from the standard input.
Comments: You can optionally display prompt text before the
variable name.
The /W(ait) option allows you to specify a timeout
period, where n is the number of seconds to wait for a
response. If no keystroke is entered by the end of the
timeout period, INPUT returns with the variable unchanged.
If you enter a key before the timeout period, INPUT will
wait indefinitely for the remainder of the line. You can
specify /W0 to check if a key is already in the buffer,
and return immediately.
All characters entered up to, but not including, the
carriage return are stored in the variable.
INPUT and INKEY are normally used in batch files,
allowing you great flexibility in entering or changing
batch variables.
See also INKEY.
Example: The following batch file fragment prompts for a string
and stores it in the variable FNAME:
input Enter the file name: %%fname
4DOS Reference Manual Copyright 1991, JP Software Inc. 93
KEYSTACK
Syntax: KEYSTACK ["abc"] [nn] [@nn] [!]
Purpose: Feed keystrokes to a program from a batch file or
alias.
Comments: Characters entered within double quotes ("abc") will be
stored "as is" in the keyboard buffer. Numbers (nn) not
enclosed in quotes are ASCII decimal codes (e.g., 13
(ENTER), or 27 (ESCAPE)). The number 0 is a special case;
it is used with programs that flush the keyboard buffer
(it tells the program the buffer is clear, so subsequent
keystrokes will be accepted normally). Numbers preceded
by @ are extended keyboard codes generated by the Alt key,
cursor pad keys, and the Function keys (e.g., @59 is the
F1 function key). See Appendix C for a list of the
extended key codes. A ! will clear all pending keystrokes,
both in the KEYSTACK buffer and in the keyboard buffer.
Some programs require both the keyboard "scan code" and the
ASCII code to be stacked. To stack both codes calculate the
value ((256 * scan) + ASCII) and use that for KEYSTACK. For
example for ENTER the scan code is 28 and the ASCII code is
13, so to stack both values use KEYSTACK 7181 (7181 is 256 *
28 + 13). Scan code tables are available in many PC
reference books.
You can store a maximum of 255 characters.
Each time KEYSTACK is executed, it will clear any
remaining keystrokes stored by a previous KEYSTACK.
You may need to experiment a bit with your programs to
find the proper sequence of keystrokes. Programs that
bypass MS-DOS and the BIOS for keyboard input cannot read
keystrokes entered with KEYSTACK.
KEYSTACK requires the device driver KEYSTACK.SYS be
loaded in the CONFIG.SYS file (see Installation).
Example: The following batch file starts Lotus 1-2-3 and loads
the file specified on the command line:
pushd c:\123
keystack 0 13 0 13 0 13 0 13 0 13 "/FR" 0 "%1" 13
123
popd
The same command defined as an alias (enter this on one
line):
alias 321 `pushd c:\123 ^ keystack 0 13 0 13 0 13 0
13 0 13 "/FR" 0 "%1" 13 ^ 123 ^ popd`
4DOS Reference Manual Copyright 1991, JP Software Inc. 94
LIST
Syntax: LIST [/HSW] [d:][path]filename...
Purpose: Display a file with forward and backward paging and
scrolling.
Comments: LIST provides a much faster and more flexible way to view a
file than TYPE, without the overhead of using a text editor.
The /H option strips the high bit from each character
before displaying. This is useful when displaying files
created by some word processors that turn on the high bit
for formatting purposes.
The /S option will read from the standard input rather than
a file. This allows you to redirect command output and view
it with LIST.
The /W option will wrap the text at the right margin. This
option is useful when displaying non-text files.
LIST uses the cursor pad to scroll through the file. The
following keys have special meanings (the caret ^ means
press the Control key together with with the specified key):
Home Display the first page of the file.
End Display the last page of the file.
Esc Exit the current file.
^C Quit LIST.
Up Arrow Scroll up one line.
Down Arrow Scroll down one line.
Left Arrow Scroll left 8 columns.
Right Arrow Scroll right 8 columns.
^Left Arrow Scroll left 40 columns.
^Right Arrow Scroll right 40 columns.
F1 Call the on-line help (HELP.EXE).
F Prompt and search for a string (case is
ignored).
N Find next matching string (case is
ignored). LIST saves the search
string, so you can LIST multiple files
and search for the same string simply
by pressing N in each file.
P Print the file on LPT1.
LIST is normally only useful for displaying ASCII text
files; executable files (.COM and .EXE) and many data
files will be unreadable due to the presence of non-
alphanumeric characters.
See also TYPE.
4DOS Reference Manual Copyright 1991, JP Software Inc. 95
Example: Display the file MEMO.DOC:
c:\> list memo.doc
Display the output from a DIR command:
c:\> dir | list /s
Redefine the DIR command to always display its output
via LIST:
c:\> alias dir `*dir %& | list /s`
4DOS Reference Manual Copyright 1991, JP Software Inc. 96
LOG
Syntax: LOG [/W [d:][path]filename | ON | OFF | text]
Purpose: Save a log of commands to a disk file.
Comments: LOG defaults to saving to the file 4DOSLOG in the root
directory of the boot drive.
Entering LOG with no parameters displays the log status
(ON or OFF). Entering LOG with text writes the text to
the log file, even if LOG is set OFF. This allows you to
enter headers in the log file.
You can specify a different filename with the /W(rite)
switch. The /W switch automatically enables command
logging.
The commands are stored in the log file as they were
entered, before performing any alias or variable
expansion.
The LOG file format looks like:
[mm/dd/yy hh:mm:ss] command
Example: Display the LOG status:
c:\> log
LOG is OFF
Enable command logging:
c:\> log on
Enable command logging to the file C:\LOG\LOGFILE and
insert a header:
c:\> log /w c:\log\logfile
c:\> log "Started work on the database system"
4DOS Reference Manual Copyright 1991, JP Software Inc. 97
MD / MKDIR
Syntax: MD [d:]pathname...
or
MKDIR [d:]pathname...
Purpose: Create subdirectories.
Comments: To start at the root directory, start the pathname with
a backslash (\). To start at the parent directory, start
the pathname with two periods (..). All other pathnames
start at the current directory.
The longest allowable path in MS-DOS from the root
directory to any subdirectory is 64 characters (including
backslashes).
See also RD.
Example: Create a subdirectory called MYDIR in the root
directory:
c:\> md \mydir
Create a subdirectory called DIRTWO in the current
directory:
c:\mydir> md dirtwo
4DOS Reference Manual Copyright 1991, JP Software Inc. 98
MEMORY
Syntax: MEMORY
Purpose: Display the system RAM status.
Comments: MEMORY displays the total RAM, the free RAM (available
to applications programs after loading MS-DOS, device
drivers, 4DOS itself, and RAM resident programs); the
total and free expanded memory, extended memory and XMS
memory (on an 80286 or 80386); the total and free
environment space; the total and free alias list space;
and the total command history space.
If you compare the free RAM displayed by MEMORY with
the free RAM displayed by CHKDSK and some memory map
programs, MEMORY will usually show a slightly higher
value. The difference is the size of the environment
passed to these external programs; most memory mapping
programs do not count the passed environment as free
space.
Example: Display your RAM totals:
c:\> memory
655,360 bytes total RAM
534,464 bytes free
1,687,552 bytes total EMS memory
1,097,728 bytes free
914,432 bytes total XMS memory
512 bytes total environment
195 bytes free
1,024 bytes total alias
452 bytes free
1,024 bytes total history
4DOS Reference Manual Copyright 1991, JP Software Inc. 99
MOVE
Syntax: MOVE [/PQR] [d:][path]filename... [d:][path]filename
Purpose: Move files to other directories and drives.
Comments: The MOVE command moves the specified file(s) to the last
filename specified, which is designated as the target. If
the target already exists, it is deleted when the file is
moved. You cannot move a file to a character device or to
itself.
If there is more than one source file specification,
the target must be a directory, and the files are moved to
the directory with their original filenames. If the
target is not a directory, MOVE will display an error
message and exit.
Use caution when using MOVE with commands like SELECT.
If multiple files are SELECTed and the target is not a
subdirectory, each file will be moved in turn to the
target, overwriting the previous file. The net result is
that all files but the last will be deleted. If SELECT is
invoked using square brackets instead of parentheses, the
MOVE will be done in a single command and MOVE will detect
the error.
The /P(rompt) option will prompt you for a Y or N
response to confirm each move.
The /Q(uiet) option turns off the display of the files moved.
The /R(eplace) option will prompt you for a Y or N
response before overwriting an existing file.
MOVE first attempts to rename the file(s). If that
fails (the target is on a different drive, or the target
already exists), MOVE will copy the file(s) and then
delete the originals. If MOVE cannot delete the original
(for example, a read-only file), it will display an error
message, but the target file is still created.
See also COPY and RENAME.
4DOS Reference Manual Copyright 1991, JP Software Inc. 100
Example: Move some files to a different directory:
c:\> move *.wks *.txt c:\finance\myfiles
Move all the files in the current directory to A:\,
prompting before overwriting any existing files:
c:\> move /r *.* a:\
4DOS Reference Manual Copyright 1991, JP Software Inc. 101
PATH
Syntax: PATH [[d:]path;[d:]path...]]
Purpose: Tells 4DOS where to search for executable and batch
files not in the current directory.
Comments: When searching for an external command (.COM, .EXE,
.BTM, and .BAT), 4DOS searches the current directory
first, then the directories you specify in the order you
list them. The directory names are separated by
semicolons (;). Like COMMAND.COM, 4DOS shifts the entire
path to upper case before storing it in the environment.
This maintains compatibility with programs which can only
recognize an upper case path.
If you enter PATH with no parameters, 4DOS displays the
current search path. If you enter PATH and a semicolon,
4DOS clears the search path and will search only the
current directory (this is the default at system startup).
If you specify an invalid directory, 4DOS will skip
that directory and continue searching with the next
directory in the path.
Some applications use the PATH variable to search for
their files.
You can edit the path with the ESET command.
Example: The following PATH command directs 4DOS to search for
an executable file in the following order: the current
directory, the root directory on C, the DOS subdirectory
on C, and the UTIL subdirectory on C:
c:\> path c:\;c:\dos;c:\util
Display the current search path:
c:\> path
PATH=C:\;C:\DOS;C:\UTIL
4DOS Reference Manual Copyright 1991, JP Software Inc. 102
PAUSE
Syntax: PAUSE [message]
Purpose: Suspend alias or batch file execution.
Comments: A PAUSE command will suspend execution, giving you the
opportunity to perform activities such as changing disks,
turning on the printer, etc.
PAUSE flushes the keyboard buffer, and then waits for
any key (except ^C or ^BREAK) to be pressed and then
continues executing. If a prompt message is specified,
4DOS will display the message and wait for a keystroke.
Otherwise, 4DOS will prompt:
Press a key when ready...
If you press ^C or ^BREAK while PAUSE is waiting for a
key, execution of an alias will be terminated, and
execution of a batch file will be suspended while you are
prompted whether to cancel the batch job (see Batch Files
in Using 4DOS).
Example: The following batch file fragment prompts the user
before erasing files:
pause ^C aborts, any other key erases the .LST files
erase *.lst
4DOS Reference Manual Copyright 1991, JP Software Inc. 103
POPD
Syntax: POPD [*]
Purpose: Change to the disk drive and directory at the top of
the directory stack.
Comments: POPD restores the disk drive and directory saved using
PUSHD (most recent first).
The * option clears the directory stack, without
changing the current drive and directory.
Use the DIRS command to display the directory stack.
See also DIRS and PUSHD.
Example: Save and change your disk drive and directory with
PUSHD, and then restore it:
c:\> pushd d:\database\test
d:\database\test> pushd c:\wordp\memos
c:\wordp\memos> pushd a:\123
a:\123> popd
c:\wordp\memos> popd
d:\database\test> popd
c:\>
Clear the directory stack:
c:\> popd *
4DOS Reference Manual Copyright 1991, JP Software Inc. 104
PROMPT
Syntax: PROMPT [text]
Purpose: Change the 4DOS command line prompt.
Comments: If you enter PROMPT with no arguments, 4DOS sets the
prompt on drives A and B to $n$g, and on all other drives
to $p$g (display current disk and directory).
The prompt text can contain special strings of the form
$?, where ? is one of the following characters.
b The | character
c The open parenthesis (
d Current date, in the format Tue Jan 1, 1991 (US
and Japan) or Tue 1. Jan 1991 (Europe)
e The ASCII ESC character (decimal 27)
f The close parenthesis )
g The > character
h BACKSPACE over the previous character
l The < character
n Default drive letter
P Current disk and directory (upper case)
p Current disk and directory (lower case)
q The = character
s The space character
t Current time, in the format hh:mm:ss
v MS-DOS version number, in the format 3.10
Xd: Current disk and directory (upper case) where d is
the drive specification
xd: Current disk and directory (lower case) where d is
the drive specification
z Display the current 4DOS shell nesting level (you
must be running 4DOS as the primary shell in
swapping mode). The primary command processor is
0. Resident copies of 4DOS return a 99 for the
shell nesting level.
$ The $ character
_ CR/LF (go to beginning of new line)
4DOS Reference Manual Copyright 1991, JP Software Inc. 105
Under COMMAND.COM, it is possible to use the PROMPT
command in a batch file to transmit ANSI.SYS control
sequences to the screen (for example, to redefine function
keys). This is because COMMAND.COM displays a prompt when
echoing lines in a batch file. This technique will not
work with 4DOS, because 4DOS doesn't display a prompt
within batch files; hence the characters in the PROMPT
string are never sent to ANSI.SYS. To send ANSI sequences
in 4DOS, use the ECHO command, substituting e (control-X
followed by an e) for $e in the PROMPT string.
Example: Set the prompt to the current date and time:
c:\> prompt $d $t $g
Mon Dec 25, 1989 18:29:19 >
Set a prompt using ANSI escape sequences to display the
shell level, date, time and path in color on the top line
(enter as one line):
c:\> prompt $e[s$e[1;1f$e[41;1;37m$e[K[$z] $d Time:
$t$h$h$h Path: $p$e[u$e[0;32m$n$g
4DOS Reference Manual Copyright 1991, JP Software Inc. 106
PUSHD
Syntax: PUSHD [[d:]pathname]
Purpose: Save the current disk drive and directory.
Comments: PUSHD saves the current disk and directory on the
directory stack, and if a pathname is specified on the
command line, changes the disk drive and directory. The
directory stack can hold up to 255 characters (about 10 to
20 entries). If you exceed the directory stack size, the
oldest directory is removed before adding the current
directory.
The saved directory is restored on a "last in, first
out" basis by the POPD command. The directory stack can
be displayed with the DIRS command.
See also CDD, DIRS and POPD.
Example: Save the current directory and change to C:\WORDP\MEMOS:
c:\> pushd \wordp\memos
c:\wordp\memos>
Save the current drive and directory, without changing
directories:
c:\> pushd
c:\>
4DOS Reference Manual Copyright 1991, JP Software Inc. 107
QUIT
Syntax: QUIT
Purpose: Terminate the current batch file.
Comments: You can QUIT at any point in a batch file, not just at
the end.
If you QUIT a batch file called from another batch
file, you will be returned to the previous file at the
line following the original call. To end all batch file
processing, use CANCEL.
See also CANCEL.
Example: This batch file fragment checks to see if the user
entered "quit" and exits if true.
input Enter your choice : %%option
if "%option" == "quit" quit
4DOS Reference Manual Copyright 1991, JP Software Inc. 108
RD / RMDIR
Syntax: RD [d:]path...
or
RMDIR [d:]path...
Purpose: Remove one or more subdirectories.
Comments: Before removing a subdirectory, you must delete all the
files and subdirectories (and their files) in that
directory (including any hidden or read-only files).
You can use the MS-DOS wildcard characters (* and ?) in
the directory names.
You cannot remove the root directory (\), the current
directory (.), or the parent directory (..).
See also MD.
Example: Remove the subdirectory MEMOS from the subdirectory WP:
c:\> rmdir \wp\memos
4DOS Reference Manual Copyright 1991, JP Software Inc. 109
REM
Syntax: REM [comment]
Purpose: Put a comment in a batch file.
Comments: If ECHO is ON, or the variable VERBOSE (see the SETDOS
command) is set, 4DOS will echo the comment. Otherwise,
4DOS will ignore it. If you don't want to echo the line,
preface REM with the @ character.
Enter your comment following the REM, separated by a
space or tab. Comments can be up to 255 characters. 4DOS
will ignore everything following a REM, including quote
characters, the redirection symbols (| > <), the command
separator character, aliases, and environment variables.
Batch file comments are useful for documenting the
purpose for a batch file and the procedures used.
Example: Enter comments in a batch file:
rem This batch file provides a
rem menu-based system for accessing
rem the word processing utilities.
rem Clear the screen and get selection
cls
4DOS Reference Manual Copyright 1991, JP Software Inc. 110
REN / RENAME
Syntax: REN [/PQ] [d:][path]filename... [d:][path]filename
or
RENAME [/PQ] [d:][path]filename... [d:][path]filename
Purpose: Rename files or subdirectories.
Comments: The last filename is the new name; preceding names are
the files or directories to be renamed. You can use the
wildcard characters (* and ?) in the filenames. The new
filename must not already exist. You cannot rename a
subdirectory to a new path!
If the /P(rompt) option is specified, 4DOS will prompt
you to enter Y or N to confirm each rename.
The /Q(uiet) option turns off the display of the files
renamed.
RENAME in COMMAND.COM only allows a path to be
specified with the first file name; the path for the
target is always assumed to be the same as the source.
4DOS allows you to optionally select the target path,
renaming the source file to a new directory on the same
disk drive. If you don't specify a path for the target,
4DOS will assume a "COMMAND.COM compatible" RENAME, and
will rename the source file to the new name without moving
it to another directory.
If you want to rename to a different drive, use MOVE.
Example: Rename the file MEMO.TXT to OFFICE.TXT:
c:\> rename memo.txt office.txt
Rename the files MEMO.TXT and MEMO2.TXT to another
directory:
c:\> rename memo.txt memo2.txt c:\wp\memos
Rename the directory \WORDPROC to \WP:
c:\> rename \wordproc \wp
4DOS Reference Manual Copyright 1991, JP Software Inc. 111
RETURN
Syntax: RETURN
Purpose: Return from a GOSUB (subroutine) call in a batch file.
Comments: The RETURN command returns from a GOSUB call to the
command following the original GOSUB.
See also GOSUB.
Example: The following batch file fragment calls a subroutine
which displays the current directory:
echo Calling a subroutine
gosub subr1
echo Returned from the subroutine
quit
:subr1
dir /hw
return
4DOS Reference Manual Copyright 1991, JP Software Inc. 112
SCREEN
Syntax: SCREEN row column [message]
Purpose: Position the cursor on the screen, and optionally
display a message.
Comments: The row and column are zero-based, so on a standard 25
line by 80 column display, valid rows are 0 - 24 and valid
columns are 0 - 79.
SCREEN allows you to create attractive batch file
screen displays.
SCREEN does not change the screen colors. If you have
ANSI.SYS installed and have set colors with CLS or COLOR,
those colors will be used for the display. To display
text in specific colors, use SCRPUT.
SCREEN checks for a valid row and column, and displays
an error message if either value is out of range.
See also ECHO, SCRPUT and TEXT.
Example: The following batch file fragment displays a menu:
@echo off ^ cls
screen 3 10 Select a number from 1 to 4:
screen 6 20 1 - Word Processing
screen 7 20 2 - Spreadsheet
screen 8 20 3 - Telecommunications
screen 9 20 4 - Quit
4DOS Reference Manual Copyright 1991, JP Software Inc. 113
SCRPUT
Syntax: SCRPUT row column [bright] [blink] fg ON bg text
Purpose: Display text in color.
Comments: The row and column are zero-based, so on a standard 25
line by 80 column display, valid rows are 0 - 24 and valid
columns are 0 - 79.
SCRPUT works like SCREEN, but allows you to specify the
display colors, and writes directly to the screen.
The parameters are:
row Start row
col Start column
fg Foreground character color
bg Background character color
Only the first three characters of the color name and
attributes ("bright" and "blink") are required. The
available colors are:
Black Blue Green Red
Magenta Cyan Yellow White
See also CLS, ECHO, SCREEN and TEXT.
Example: The following batch file fragment displays a menu in
color (all commands should be entered on one line):
@echo off ^ cls white on blue
scrput 3 10 bri white on blue Select a number from 1
to 4:
scrput 6 20 bri red on blue 1 - Word Processing
scrput 7 20 bri yellow on blue 2 - Spreadsheet
scrput 8 20 bri green on blue 3 - Telecommunications
scrput 9 20 bri magenta on blue 4 - Quit
4DOS Reference Manual Copyright 1991, JP Software Inc. 114
SELECT
Syntax: SELECT [/Oeirtuz] [command] ([d:][path]filename...)...
Purpose: Execute a command on the specified files.
Comments: SELECT allows you to select command line file arguments
by marking the directory entries using a full-screen
"point-and-shoot" display. SELECT substitutes the
selected files for the argument enclosed in parentheses,
and executes the command for each marked file. The
command can be an alias, internal or external command, or
batch file. If you don't specify a command, the selected
filename(s) will become the command (see example).
The command can be a 4DOS internal command or alias, an
external command, or a batch file.
If you join filenames with a plus (+) sign, SELECT will
display the files together (an "include list"). Only the
first file in an include list can have a pathname;
subsequent filenames default to the same path.
If the filenames are enclosed in square brackets
instead of parentheses, SELECT will substitute all of the
selected filenames on one command line. If there are too
many filenames to fit on the line, SELECT will display an
error message and exit. All internal 4DOS commands
support 255 character command lines, but MS-DOS only
supports 127 character command lines for external
programs. SELECT displays the approximate command line
length in the upper left corner; it is your responsibility
to ensure SELECT doesn't exceed the 127 character limit
for external commands.
SELECT uses the up arrow, down arrow, PgUp, and PgDn
keys to scroll through the files matching the argument(s).
Use the + key or the spacebar to select a file (or
unselect a marked file), and the - key to unselect a file.
The * key will select all of the files (excluding
subdirectories). After marking the files, press ENTER to
execute the command. You can select a single file by
moving the scroll bar to the filename and pressing ENTER
when no other files have been marked.
4DOS Reference Manual Copyright 1991, JP Software Inc. 115
The /O option determines the sort order for the
directory display (the default sort is by filename):
e Sort by extension
i Sort by description (see DESCRIBE)
r Reverse the sort order
t Sort by time (oldest first)
u Unsorted
z Sort by size
If you want to use filename completion (see Command
Line Editing in Using 4DOS) to enter the filenames inside
the parentheses, type a space after the "(". Otherwise
the command line editor will treat "(" as the first
character of the filename.
To cancel the SELECT command, type an Escape, ^C, or
^BREAK.
Example: Select from the files in the current directory with the
extension .COM, and then from the files with the extension
.EXE to copy to the root directory on drive A:
c:\> select copy (*.com *.exe) a:\
Define an alias that selects from the executable files
in the directory C:\UTIL, and then executes them in the
order marked (the alias should be entered on one line):
c:\> alias utils select
(c:\util\*.com+*.exe+*.btm+*.bat)
c:\> utils
Select from all the files in the current directory to
move to the root directory on A (since the argument list
is enclosed in square brackets, this will be done by a
single command):
c:\> select move [*.*] a:\
4DOS Reference Manual Copyright 1991, JP Software Inc. 116
SET
Syntax: SET [/P] [/R filename...] [variable[=][value]]
Purpose: Display, create, modify, or delete environment
variables.
Comments: Entering SET with no variable or value displays the
environment. If you don't enter a value, SET will remove
the variable from the environment. Otherwise, the
variable and the value are placed in the environment. If
the variable already exists, its old contents are replaced
by the new value. 4DOS limits the variable name to a
maximum of 80 characters, and the value to a maximum of
255 characters. The variable names are shifted to upper
case before being stored in the environment; the value is
stored exactly as entered.
The /P option will pause after displaying a page of
environment entries. Press ^C to quit, or any other key
to display the next page.
The /R(ead) option allows you to load environment
variables from a file. This is much faster than loading
variables from a batch file. The file is in the same
format as the SET display, so SET /R can accept as input a
file generated by redirecting SET output. You can load
multiple files with one SET /R command by placing the
names one after another on the command line, separated by
spaces.
For example, the following commands will save the
environment variables to a file, and then reload them from
that file:
set > varlist
set /r varlist
You can add comments to a variable file by starting the
comment line with a colon (:).
SET only affects the environment of the current command
processor. If you EXIT to a parent command processor, the
original environment will be unchanged. The size of the
environment is specified by the /E parameter at startup.
The default size is 512 characters, the minimum size 256
characters, and the maximum size 32000 characters.
4DOS Reference Manual Copyright 1991, JP Software Inc. 117
You can remove multiple environment variables with the
UNSET command.
You can edit environment variables and aliases with the
ESET command. To enter aliases, use ALIAS.
See also UNSET and ESET.
Example: Display the current environment:
c:\> set
COMSPEC=C:\4DOS.COM
PATH=C:\;C:\DOS;C:\UTIL
Add a variable to the environment:
c:\> set mine=c:\finance\myfiles
c:\> set
COMSPEC=C:\4DOS.COM
PATH=C:\;C:\DOS;C:\UTIL
MINE=c:\finance\myfiles
Remove a variable from the environment:
c:\> set mine
c:\> set
COMSPEC=C:\4DOS.COM
PATH=C:\;C:\DOS;C:\UTIL
4DOS Reference Manual Copyright 1991, JP Software Inc. 118
SETDOS
Syntax: SETDOS [/A? /C? /E? /H? /I+|-command /L? /M? /N? /R?
/S?:? /U? /V?]
Purpose: Display or set 4DOS configuration variables.
Comments: SETDOS allows you to customize 4DOS to your personal
tastes. You would normally define the SETDOS variables in
your AUTOEXEC.BAT or 4START file. The SETDOS options are:
A The ANSI variable determines whether 4DOS will
attempt to use an ANSI escape sequence for CLS.
4DOS normally determines this itself, but if you
are using a non-standard ANSI driver or your
loading sequence is unusual, you may need to
explicitly inform 4DOS. /A0 allows 4DOS to
determine whether an ANSI driver is installed; /A1
forces 4DOS to assume an ANSI driver is installed.
C The COMPOUND variable is the character used for
separating multiple commands on the same line.
The default character is the caret (^). You
cannot use any of the redirection characters (| >
<), or any of the whitespace characters (=,;) as
the command separator.
E The ESCAPE variable is the character used to suppress
the normal meaning of the following character. Any
character following the escape character will be
passed unmodified to the command line. The default
escape character is ^X (Ctrl-X, displayed as an up
arrow). You cannot use any of the redirection
characters (| > <) or the whitespace characters
(=,;) as the escape character.
H The HISTORY variable determines the minimum command
size to save. Any command line whose length is
less than this value will not be saved to the
history list. Setting /H to 256 will disable
history saves; setting it to 0 will save
everything. The default value is 0 (save all
command lines).
4DOS Reference Manual Copyright 1991, JP Software Inc. 119
I The INTERNAL variable allows you to disable or
enable internal 4DOS commands. To disable a
command, precede the command name with a minus (-).
To reenable a command, precede it with a plus (+).
L The LINE variable controls how 4DOS gets its input
from the command line. The default value is 0
(character input). If you set /L to 1, 4DOS uses
the INT 21 0Ah "Get Line" call (like COMMAND.COM).
Note that this will disable command line editing,
history recall, and filename expansion. If you
have an program that requires line input, you can
define an alias or batch file:
setdos /L1 ^ program %& ^ setdos /L0
See the file COMPAT.DOC for information on
programs which require this option.
M The MODE variable controls the line editing mode.
4DOS defaults to overstrike mode (/M0). If MODE
is set to 1, the default is insert mode.
N The NOCLOBBER variable controls output redirection.
If NOCLOBBER is set to 1, then existing files may
not be destroyed by output redirection, and when
appending with >>, the output file must exist.
NOCLOBBER can be overridden with the ! character
(see the section on redirection in Using 4DOS).
The default value is 0.
R The ROWS variable sets the number of screen rows
used by the video display. Normally 4DOS detects
the screen size, but if you have a non-standard
display you may need to set it explicitly. The
ROWS variable does not affect screen scrolling
(that is controlled by your video BIOS or
ANSI.SYS); it is used only for LIST, SELECT, the
paged output options (i.e., TYPE /P), and error
checking in the screen output commands.
4DOS Reference Manual Copyright 1991, JP Software Inc. 120
S The SHAPE variable sets the 4DOS cursor shape. The
format is /Ss:e where s is the starting scan line
and e the ending. The default values are the last
two lines of the cursor cell. The default editing
mode (see /M above) uses the default cursor shape;
the other mode sets the starting scan line to 0
and displays a block cursor.
U The UPPER variable controls the way filenames are
displayed for the internal commands (COPY, DIR,
etc.). If UPPER is set to 1, filenames will be
displayed in upper case (like COMMAND.COM). UPPER
defaults to /U0 (filenames will be displayed in
lower case).
V The VERBOSE variable controls command echoing in
batch files. If VERBOSE is set to 0, batch file
commands will NOT be echoed unless ECHO is set ON.
VERBOSE defaults to 1 (that is, batch file
commands WILL be echoed).
Example: Change the COMPOUND character to a ~ (tilde):
c:\> setdos /c~
Change MODE to insert, VERBOSE to off, and set
NOCLOBBER on:
c:\> setdos /m1 /v0 /n1
Disable the internal LIST command to force 4DOS to use
an external command:
c:\> setdos /i-list
4DOS Reference Manual Copyright 1991, JP Software Inc. 121
SETLOCAL
Syntax: SETLOCAL
Purpose: Save a copy of the current disk drive, directory,
environment variables, and aliases.
Comments: SETLOCAL is used in batch files to save the disk drive,
directory, environment variables and aliases to a reserved
block of memory. You can then change their values, and
later restore the original values with ENDLOCAL. You
cannot use SETLOCAL in an alias.
SETLOCAL and ENDLOCAL are not nestable within the same
batch file. However, you can have multiple SETLOCAL /
ENDLOCAL pairs within a batch file, and nested batch files
can each have their own SETLOCAL / ENDLOCAL. 4DOS will
automatically perform an ENDLOCAL at the end of a batch
file.
Note that if you invoke a batch file from another
without using CALL, the first batch file is implicitly
terminated, and an automatic ENDLOCAL performed. The
second batch file will inherit the drive, directory,
environment variables, and aliases as they were prior to
the SETLOCAL.
Do not load TSRs (memory-resident programs) from a
batch file while a SETLOCAL is in effect. If you do, when
ENDLOCAL is executed and the memory used by SETLOCAL is
released, a "hole" will be left in memory below the TSR.
This is not harmful, but wastes memory.
See also ENDLOCAL.
Example: This batch file fragment saves the disk drive,
directory, environment variables and aliases, changes the
disk and directory, modifies some variables, runs a
program, and then restores the original values:
setlocal
cdd d:\test ^ set path=c:\;c:\dos;c:\util
set lib=d:\lib
rem run some program here
endlocal
4DOS Reference Manual Copyright 1991, JP Software Inc. 122
SHIFT
Syntax: SHIFT [n]
Purpose: Allow the use of more than 10 variables in a batch
file.
Comment: SHIFT is provided for compatibility with COMMAND.COM.
COMMAND.COM supports only 10 parameters (%0 through %9);
4DOS supports 128 parameters (%0 to %127), so you may not
need to use SHIFT for batch files running exclusively
under 4DOS.
SHIFT moves each of the batch file parameters n
positions (i.e., %1 becomes %0, %2 becomes %1, etc.). The
default value for n is 1. You can also reverse a SHIFT,
by giving a negative value for n (i.e., if n is -1, the
former value for %0 is restored, %0 becomes %1, %1 becomes
%2, etc.).
SHIFT also affects the %n& (command line tail) and %#
(number of command arguments) batch variables.
Example: Create a batch file called TEST.BAT:
echo %1 %2 %3 %4
shift
echo %1 %2 %3 %4
shift 2
echo %1 %2 %3 %4
shift -1
echo %1 %2 %3 %4
Executing TEST.BAT produces the following results:
c:\> test zero one two three four five six
zero one two three
one two three four
three four five six
two three four five
4DOS Reference Manual Copyright 1991, JP Software Inc. 123
SWAPPING
Syntax: SWAPPING [on | off]
Purpose: Display, enable, or disable the 4DOS swapping state.
Comments: SWAPPING will temporarily disable or enable the
swapping of the 4DOS transient portion to EMS, XMS, or
disk (see Installation). This is particularly useful when
running batch files while swapping to disk. If swapping
is enabled, 4DOS saves its transient portion before
executing any external command. When the command
finishes, 4DOS performs a checksum on the transient
portion (when swapping to disk), and restores it if
necessary. (When swapping to EMS or XMS, 4DOS always
restores the transient portion.) When you are running
several small programs from a batch file and using disk
swapping, the swapping can sometimes cause a noticeable
delay. Turning SWAPPING OFF can speed up such operations.
If SWAPPING is OFF, available MS-DOS memory will be
reduced by the size of the 4DOS transient portion (about
70K). Setting SWAPPING OFF does not close the disk swap
file, or release any reserved EMS or XMS memory.
Setting SWAPPING OFF can be useful in speeding up your
AUTOEXEC.BAT file.
Example: Check the current SWAPPING status:
c:\> swapping
SWAPPING is ON
The following batch file fragment disables swapping,
runs several programs, and then reenables swapping:
swapping off
c:\util\mouse
c:\video\ansi.com
cls bright white on blue
c:\bin\cache.com
swapping on
4DOS Reference Manual Copyright 1991, JP Software Inc. 124
TEE
Syntax: TEE [/A] [d:][path]filename...
Purpose: Copy standard input to standard output, and save a copy
in the specified file(s).
Comments: The /A option causes the output to be appended to the
file(s) rather than overwriting it.
If you are typing at the keyboard, you need to enter a
^Z to terminate the input.
TEE is often used to save the intermediate output of a
pipe.
See also Y.
Example: Search the file DOC for any lines containing the string
"4DOS", make a copy of the matching lines in 4.DAT, sort
the lines, and write them to the output file 4DOS.DAT:
c:\> find "4DOS" doc | tee 4.dat | sort > 4dos.dat
4DOS Reference Manual Copyright 1991, JP Software Inc. 125
TEXT
Syntax: TEXT
.
.
.
ENDTEXT
Purpose: Display a block of text in a batch file.
Comments: The TEXT command is useful for displaying menus or
multiple line messages. TEXT will display subsequent
lines in the batch file until terminated by ENDTEXT. Both
TEXT and ENDTEXT must be entered as the only command on
that line.
If you have ANSI.SYS loaded, you can change screen
colors by inserting ANSI escape sequences into the text
block.
See also ECHO, SCREEN and SCRPUT.
Example: The following batch file fragment displays a simple
menu:
@echo off ^ cls ^ screen 2 0
text
Enter one of the following:
1 - Spreadsheet
2 - Word Processing
3 - DOS Utilities
Enter your selection :
endtext
4DOS Reference Manual Copyright 1991, JP Software Inc. 126
TIME
Syntax: TIME [hh[:mm[:ss]][am | pm]
Purpose: Display or set the current system time.
Comments: If you don't enter any parameters, TIME will display
the current system time and prompt you for a new time.
Press ENTER if you don't wish to change the time,
otherwise enter the new time.
The parameters for the TIME command are:
hh (hour) = 0 - 23
mm (minute) = 0 - 59
ss (second) = 0 - 59
TIME defaults to 24-hour format, but you can optionally
enter the time in 12-hour format by appending an "am" or
"pm".
Whenever you create or modify a file, the system time
is recorded in the directory entry.
Example: Enter the time (9:30 am):
c:\> time 9:30
To be prompted for the time:
c:\> time
Mon Dec 25, 1989 9:30:10
New time (hh:mm:ss):
4DOS Reference Manual Copyright 1991, JP Software Inc. 127
TIMER
Syntax: TIMER [/S]
Purpose: System stopwatch.
Comments: The TIMER command turns the system stopwatch on and
off. The first time you run TIMER, the stopwatch starts.
When you run TIMER again, the stopwatch stops and the
elapsed time is displayed.
The /S option allows you to display a split time
without stopping the timer.
TIMER is particularly useful for timing events in batch
files.
The smallest interval TIMER can measure is .06 seconds;
the largest interval is 23:59:59.99.
Example: Start the timer:
c:\> timer
Timer on: 12:21:46
Display the current time, leaving the timer running:
c:\> timer /s
Elapsed time: 0:00:08.90
Stop the timer:
c:\> timer
Timer off: 12:21:58 Elapsed time: 0:00:12.06
4DOS Reference Manual Copyright 1991, JP Software Inc. 128
TYPE
Syntax: TYPE [/LP] [d:][pathname]filename...
Purpose: Display the contents of the specified file(s).
Comments: The TYPE command displays a file. Press ^S to suspend
the display, and any character key to continue the
display.
The /L option prints line numbers preceding each line
of text.
The /P option will pause after each page. Press ^C to
quit, or any other key to display the next page.
TYPE is normally only useful for displaying ASCII text
files; executable files (.COM and .EXE) and many data
files may be unreadable due to the presence of non-
alphanumeric characters.
You will probably find LIST to be more useful for
displaying files.
See also LIST.
Example: Display the files MEMO1 and MEMO2, pausing at the end
of each page:
c:\> type /p memo1 memo2
4DOS Reference Manual Copyright 1991, JP Software Inc. 129
UNALIAS
Syntax: UNALIAS alias...
or
UNALIAS *
Purpose: Remove aliases from the alias list.
Comments: UNALIAS also accepts the wildcard character * to delete
all aliases.
See also ALIAS and ESET.
Example: Remove the alias DDIR:
c:\> unalias ddir
Remove the aliases DDIR and ZAP:
c:\> unalias ddir zap
Remove all the aliases:
c:\> unalias *
4DOS Reference Manual Copyright 1991, JP Software Inc. 130
UNSET
Syntax: UNSET name...
or
UNSET *
Purpose: Remove variables from the environment.
Comments: UNSET also accepts the wildcard character * to delete
all of the environment variables. Use caution with UNSET
*; many programs are dependent on environment variables,
and 4DOS itself relies on PATH, COMSPEC, and 4DSHELL.
See also SET and ESET.
Example: Remove the variable CMDLINE:
c:\> unset cmdline
Remove the variables CMDLINE and PATH:
c:\> unset cmdline path
Remove all the environment variables:
c:\> unset *
4DOS Reference Manual Copyright 1991, JP Software Inc. 131
VER
Syntax: VER
Purpose: Display the current 4DOS and MS-DOS versions.
Comments: The 4DOS and MS-DOS versions consist of a one digit
major version number, a period, and a one or two digit
minor version number.
Example: Get the current version of 4DOS and MS-DOS:
c:\> ver
4DOS 3.03 DOS 3.31
4DOS Reference Manual Copyright 1991, JP Software Inc. 132
VERIFY
Syntax: VERIFY [on | off]
Purpose: Display, enable, or disable disk write verification.
Comments: When VERIFY is ON, MS-DOS will verify that no error
occurred during the disk write operation. It does NOT
compare the data actually written to the disk. VERIFY
will remain ON until you set it OFF.
Entering VERIFY with no parameters will display the
current VERIFY state.
Verification will slow your disk write operations
slightly.
At system startup, VERIFY is OFF.
Example: Check the current verify status:
c:\> verify
VERIFY is OFF
Enable disk write verification:
c:\> verify on
4DOS Reference Manual Copyright 1991, JP Software Inc. 133
VOL
Syntax: VOL [d:]...
Purpose: Display the disk volume label(s).
Comments: If you don't enter a drive name, VOL displays the disk
label for the current drive.
If the disk doesn't have a volume name, VOL will report
it as "unlabeled."
Volume labels can be created, changed or deleted with
the external MS-DOS LABEL command.
Example: Display the label for the default disk:
c:\> vol
Volume in drive C: is MYHARDDISK
Display the disk labels for drives A and B:
c:\> vol a: b:
Volume in drive A: is unlabeled
Volume in drive B: is BACKUP_2
4DOS Reference Manual Copyright 1991, JP Software Inc. 134
Y
Syntax: Y [d:][path]filename...
Purpose: Copy standard input to standard output, and then copy
the specified file(s) to standard output.
Comments: Standard input from the console is terminated by a ^Z.
See also TEE.
Example: Get text from standard input, append the files MEMO1
and MEMO2 to it, and send the output to MEMOS:
c:\> y memo1 memo2 > memos
4DOS Reference Manual Copyright 1991, JP Software Inc. 135
APPENDIX A - 4DOS and MS-DOS Error Messages
4DOS swapping failed, loading in memory-resident mode
None of the swapping options worked. Check your swapping
specification in SHELL or 4DSHELL, and/or free XMS or EMS memory
or disk space.
4DOS unrecoverable error XX
An error occurred in the resident portion of 4DOS. These errors
will terminate secondary shells, and require a reboot if they
occur during a primary shell.
BI Bad server function code
DI Same as Disk swap file corrupted
DR Same as Swap file read error
DS Same as Swap file seek error
ES Same as EMS map save or restore failed
EI Same as EMS mapping error
NS No number for new shell
PT Illegal process termination
TS Terminated inactive shell
XI Same as XMS move failed
Access denied
You tried to erase or write to a read-only protected file, to
rename a file or directory to an existing name, or to remove a
read-only directory or a directory with files or subdirectories
still in it.
Alias loop
An alias refers back to itself (i.e., a = b = a), or aliases are
nested more than 16 deep. Correct your alias list.
Attempt to exit from root shell
Another program has destroyed a portion of 4DOS' memory, or you
forgot a /P on your SHELL line in CONFIG.SYS. Reboot the system
and correct the error.
Bad disk unit
Generally caused by a disk drive hardware failure.
4DOS Reference Manual Copyright 1991, JP Software Inc. 136
Bad environment
The MS-DOS environment has a bad structure. Reboot the system.
Batch file missing
4DOS can't find the batch (.BAT) file it was running. It was
either deleted, renamed, moved, or the disk was changed.
Can't copy file to itself
4DOS will not permit you to COPY or MOVE a file to itself.
Unlike COMMAND.COM, 4DOS does full path and filename expansion
before copying to ensure that files aren't inadvertently
destroyed.
Can't create
4DOS can't create the specified file. The disk may be full or
write protected, the file already exists and is read-only, or the
root directory is full.
Can't delete
4DOS can't delete the specified file or directory. The disk is
probably write protected.
Can't find EXE file
The loader (4DOS.COM) can't locate either 4DOS88.EXE or
4DOS286.EXE. At boot time, one of these files must be in the
current directory, or the path must be specified with the /L
switch (see Installation). When starting a secondary shell, one
of these files must be specified with the /L switch in the
4DSHELL environment variable, or must be in the directory
specified by COMSPEC.
Can't get directory
4DOS can't read the directory. The disk drive is probably not
ready.
Can't make directory entry
4DOS can't create the filename in the directory. This is usually
caused by a full root directory. Create a subdirectory and move
some of the files to it.
4DOS Reference Manual Copyright 1991, JP Software Inc. 137
Can't open
4DOS can't open the specified file; either it doesn't exist or
the disk directory or File Allocation Table is damaged.
Can't remove current directory
MS-DOS can't delete your current directory. Change to the parent
directory and try again.
Can't set up disk swap file
The disk swap file you specified cannot be opened. The path or
drive is invalid, the disk is full, MS-DOS is out of file
handles, or there is a hardware problem. Check SHELL and
4DSHELL.
Command line too long
The command exceeded 255 characters during alias and variable
expansion, or you or your program attempted to pass a command
line exceeding 126 characters to a secondary 4DOS shell
(including the necessary alias, environment, and history
settings). Reduce the line length and/or use default alias,
environment, and history sizes.
Contents lost before copy
COPY was appending files, and found one of the source files is
the same as the target. That source file is skipped, and
appending continues with the next file.
Data error
MS-DOS can't read or write properly to the device.
Directory stack empty
POPD or DIRS can't find any entries in the directory stack.
Disk is write protected
The disk cannot be written to. Check the disk and remove the
write-protect tab if necessary.
4DOS Reference Manual Copyright 1991, JP Software Inc. 138
Disk swap file corrupted
The 4DOS disk swapping file (4DOSSWAP) has been moved, deleted,
or damaged. Reboot the system.
Drive not ready--close door
The floppy disk drive door is open. Close the door and try
again.
EMS deallocation failed
The loader (4DOS.COM) can't deallocate EMS memory when exiting
from a secondary copy of 4DOS. The EMS map has been corrupted or
the loader's memory area has been destroyed by a program. Reboot
the system.
EMS map save or restore failed
4DOS cannot save or restore the EMS page map. The EMS map has
been corrupted, or memory has been destroyed by a program, or you
have an incompatible EMS driver. Try another swapping method.
EMS mapping failed
The loader (4DOS.COM) can't map EMS pages when swapping 4DOS to
or from EMS. The EMS map has been corrupted, or the loader's
memory area has been destroyed by a program. Reboot the system.
EMS not available for swapping
You requested EMS swapping but no EMS memory was available.
Change your swapping method or free some EMS memory.
Environment already saved
You have already saved the environment with a previous SETLOCAL
command. You cannot nest SETLOCAL / ENDLOCAL pairs.
Error reading
MS-DOS experienced an I/O error when reading from a device. This
is usually caused by a bad disk, a device not ready, or a
hardware error.
4DOS Reference Manual Copyright 1991, JP Software Inc. 139
Error writing
MS-DOS experienced an I/O error when writing to a device. This
is usually caused by a full disk, a bad disk, a device not ready,
or a hardware error.
Exceeded batch nesting limit
You have attempted to nest batch files more than 4 levels deep.
EXE file [seek | read | close] failed
The loader (4DOS.COM) encountered an I/O error while attempting
to access 4DOS88.EXE or 4DOS286.EXE. Either the disk directory
or FAT is corrupted, or one of these files has been damaged. Run
CHKDSK to verify the disk is OK, and reload 4DOS88 or 4DOS286
from your distribution disk.
Fatal error -- please reboot
4DOS cannot continue due to the previous error. Reboot the
system.
File Allocation Table bad
MS-DOS can't access the FAT on the specified disk. This can be
caused by a bad disk or a hardware error.
File exists
The requested output file already exists, and 4DOS won't
overwrite it.
File not found
4DOS couldn't find the specified file. Check the spelling or
path name.
General failure
This is usually a hardware problem, particularly a disk drive
failure or a device not properly connected to a serial or
parallel port. Try to correct the problem or reboot and try
again.
Internal DOS error
MS-DOS encountered an internal bug and failed. Reboot the
system.
4DOS Reference Manual Copyright 1991, JP Software Inc. 140
Invalid date
An invalid date was entered. Check the syntax and reenter.
Invalid drive
A bad or non-existent disk drive was specified.
Invalid load path specified, ignored
You specified an invalid path in the /L option in SHELL or
4DSHELL.
Invalid MS-DOS version
You need a newer version of MS-DOS to execute the specified
command.
Invalid parameter
4DOS didn't recognize the a parameter. Check the syntax and
spelling.
Invalid path
The specified path does not exist. Check the disk specification
and/or spelling.
Invalid swap path specified, using current drive and directory
You specified an invalid path in the /S:B or /S:D option in SHELL
or 4DSHELL.
Invalid swapping option
You specified an invalid value for the /S option in SHELL or
4DSHELL.
Invalid time
An invalid time was entered. Check the syntax and reenter.
KEYSTACK.SYS not loaded
You attempted to execute a KEYSTACK command without loading
KEYSTACK.SYS in your CONFIG.SYS file (see Installation).
4DOS Reference Manual Copyright 1991, JP Software Inc. 141
Label not found
A GOTO or GOSUB referred to a non-existent label. Check your
batch file.
Memory deallocation error
The loader (4DOS.COM) can't deallocate memory while loading 4DOS.
The MS-DOS memory allocation has been corrupted. Reboot the
system.
Memory destroyed
The DOS memory control blocks have been corrupted. Reboot the
system.
Missing ENDTEXT
A TEXT command is missing a matching ENDTEXT. Check the batch
file.
Missing GOSUB
4DOS cannot perform the RETURN command in a batch file. You
tried to do a RETURN without a GOSUB, or your batch file has been
corrupted.
Missing SETLOCAL
4DOS encountered an ENDLOCAL without a matching SETLOCAL.
No aliases defined
No aliases were found in the environment.
No closing quote
4DOS couldn't find a second matching quote (` or ") on the
command line.
No file handle available
This is an internal 4DOS disk swapping error. Change to another
swapping method if possible, and contact JP Software.
No high memory available, environment will be placed in low memory
You requested loading the environment in an XMS UMB via the
/E:nnnU option in SHELL or 4DSHELL, but no UMB was available.
Check your XMS driver.
4DOS Reference Manual Copyright 1991, JP Software Inc. 142
No high memory available, resident portion will remain in low memory
You requested relocation of the 4DOS resident portion to an XMS
UMB via the /U option in SHELL or 4DSHELL, but no UMB was
available. Free some memory or check your XMS driver.
Non-DOS disk
MS-DOS can't read the disk. Either the disk is bad, or it has
been formatted by a different operating system. Reformat it as
an MS-DOS disk.
Not an alias
The specified argument is not in the 4DOS alias list.
Not an EXE file
4DOS88.EXE and/or 4DOS286.EXE is not recognized as an EXE file.
Reload the file from your distribution disk.
Not in environment
The specified argument is not in the environment.
Not ready
The specified device can't be accessed.
Not same device
This error usually appears in RENAME. You cannot rename a file
to a different disk drive.
Out of environment space
4DOS has run out of environment space. Edit the SHELL line in
CONFIG.SYS file to increase the environment size. Change the /E
parameter to read:
/E:n
where n is a number from 256 to 32000), and reboot the machine.
4DOS Reference Manual Copyright 1991, JP Software Inc. 143
Out of memory
MS-DOS or 4DOS had insufficient free memory to execute the last
command, or the DOS memory control blocks have been destroyed.
If this error occurs in a secondary shell, return to the primary
shell before running the command. Otherwise, try to free some
memory by removing memory-resident programs. If the error
persists, reboot the system.
Out of paper
MS-DOS detected an out-of-paper condition on one of the parallel
printers (LPT1, LPT2, or LPT3). Check your printer and add paper
if necessary.
Read error
MS-DOS disk read error; usually caused by a bad disk or a non-DOS
disk.
Sector not found
BIOS disk error; usually caused by a bad disk or a non-DOS disk.
Seek error
MS-DOS can't seek to the proper location on the disk. This is
generally caused by a bad disk or drive.
SETLOCAL only valid in batch file
The SETLOCAL command can only be used in a batch (.BAT or .BTM)
file, not in an alias or from the command line.
Swap file [seek | read | write] failed
The 4DOS loader (4DOS.COM) encountered an I/O error while
accessing the disk swap file (4DOSSWAP.nnn). Either the disk was
changed, or the file or loader's memory area has been destroyed
by a program. Reboot the system.
Syntax error
A command was entered with the improper format.
4DOS Reference Manual Copyright 1991, JP Software Inc. 144
Too many open files
MS-DOS has run out of file handles. Try setting FILES=20 or more
in the CONFIG.SYS file.
Transient memory allocation error
4DOS couldn't reserve memory for its transient portion (probably
in a SWAPPING OFF command). The memory control blocks have been
destroyed, or a program has fragmented memory. Reboot the
system.
Transient memory deallocation error
4DOS couldn't release memory for its transient portion (probably
in a SWAPPING ON command). The memory control blocks have been
destroyed, or a program has fragmented memory. Reboot the
system.
Unknown command
A command was entered that 4DOS didn't recognize and couldn't
find in the current search path. Check the spelling or PATH
specification.
Write error
MS-DOS disk error; usually caused by a bad disk or a non-DOS
disk.
XMS deallocation failed
4DOS could not deallocate XMS memory when exiting a secondary
shell. XMS memory has been destroyed; reboot your system.
XMS move failed
4DOS could not move data between DOS memory and XMS memory while
swapping itself. XMS memory has been destroyed; reboot your
system.
XMS not available for swapping
You requested XMS swapping but no XMS memory is available.
Change your swapping method or free some XMS memory.
4DOS Reference Manual Copyright 1991, JP Software Inc. 145
Appendix B - ASP
The authors and publisher of 4DOS are members of the Association
of Shareware Professionals (ASP), an organization formed in April
1987 to strengthen the future of shareware as an alternative to
commercial software. Its members, all of whom are programmers
who subscribe to a code of ethics, are committed to the concept
of shareware as a method of marketing.
The ASP's Standards for its members and their shareware products
are:
Programming Standards
The program meets the ASP's definition of "shareware" (i.e.,
it is not a commercial demo with a major feature disabled,
nor a time-limited program).
The program has been thoroughly tested by the author and
should not be harmful to other files or hardware if used
properly.
Documentation Standards
Sufficient documentation is provided to allow the average
user to try all the major functions of the program.
Any discussion of the shareware concept and of registration
requirements is done in a professional and positive manner.
Support Standards
The member will respond to people who send registration
payments, as promised in the program's documentation. At a
minimum, the member will acknowledge receipt of all
payments.
The member will establish a procedure for users to report,
and have acknowledged, matters such as bug reports, and will
describe such means in the documentation accompanying all
versions of the programs. The author will respond to
written bug reports from registered users when the user
provides a self-addressed, stamped envelope.
Known incompatibilities with other software or hardware and
major or unusual program limitations are noted in the
documentation that comes with the shareware (evaluation)
program.
4DOS Reference Manual Copyright 1991, JP Software Inc. 146
ASP Ombudsman Information
This program is produced by members of the Association of
Shareware Professionals (ASP). ASP wants to make sure that
the shareware principle works for you. If you are unable to
resolve a shareware-related problem with an ASP member by
contacting the member directly, ASP may be able to help.
The ASP ombudsman can help you resolve a dispute or problem
with an ASP member, but does not provide technical support
for members' products. Please write to the ASP Ombudsman
at:
ASP Ombudsman
P.O. Box 5786
Bellevue, WA 98006
or send a Compuserve message via Easyplex electronic mail to
the ASP Ombudsman, Compuserve ID number 70475,1071.
4DOS Reference Manual Copyright 1991, JP Software Inc. 147
Appendix C - Key Codes
Here are some of the extended key codes used by the INKEY and
KEYSTACK commands (see the Command Reference Guide):
F1 - @59 Alt-F1 - @104 Ctl-F1 - @94 Shift-F1 - @84
F2 - @60 Alt-F2 - @105 Ctl-F2 - @95 Shift-F2 - @85
F3 - @61 Alt-F3 - @106 Ctl-F3 - @96 Shift-F3 - @86
F4 - @62 Alt-F4 - @107 Ctl-F4 - @97 Shift-F4 - @87
F5 - @63 Alt-F5 - @108 Ctl-F5 - @98 Shift-F5 - @88
F6 - @64 Alt-F6 - @109 Ctl-F6 - @99 Shift-F6 - @89
F7 - @65 Alt-F7 - @110 Ctl-F7 - @100 Shift-F7 - @90
F8 - @66 Alt-F8 - @111 Ctl-F8 - @101 Shift-F8 - @91
F9 - @67 Alt-F9 - @112 Ctl-F9 - @102 Shift-F9 - @92
F10 - @68 Alt-F10 - @113 Ctl-F10- @103 Shift-F10 - @93
Home @71 Up @72 PgUp @73
Left @75 Right @77
End @79 Down @80 PgDn @81
Insert @82 Del @83
Ctl-Home @119 Ctl-PgUp @132
Ctl-Left @115 Ctl-Right @116
Ctl-End @117 Ctl-PgDn @118
Alt-A -@30 Alt-N -@49 Alt-1 - @120
Alt-B -@48 Alt-O -@24 Alt-2 - @121
Alt-C -@46 Alt-P -@25 Alt-3 - @122
Alt-D -@32 Alt-Q -@16 Alt-4 - @123
Alt-E -@18 Alt-R -@19 Alt-5 - @124
Alt-F -@33 Alt-S -@31 Alt-6 - @125
Alt-G -@34 Alt-T -@20 Alt-7 - @126
Alt-H -@35 Alt-U -@22 Alt-8 - @127
Alt-I -@23 Alt-V -@47 Alt-9 - @128
Alt-J -@36 Alt-W -@17 Alt-0 - @129
Alt-K -@37 Alt-X -@45
Alt-L -@38 Alt-Y -@21
Alt-M -@50 Alt-Z -@44
4DOS Reference Manual Copyright 1991, JP Software Inc. 148
Appendix D - Programming for 4DOS
From a batch file, you can test if 4DOS is loaded with the variable
function @EVAL (see Environment Variables):
if "%@eval[2+2]" == "4" echo 4DOS is loaded!
A program can test for the presence of 4DOS by making an INT 2Fh
call. On entry:
AX = D44Dh
BX = 0
If 4DOS is loaded it will return:
AX = 44DDh
BX = Version number (BL = major version, BH = minor version)
CX = 4DOS PSP segment address
DL = 4DOS shell number (0 for the root shell, 1 for the
second, etc.). The shell number is incremented each
time a new copy of 4DOS is loaded, either in a
different multitasker window (for example, DESQview),
or via nested shells.
This function is only available in swapping mode. It tells you
if 4DOS is loaded in memory, but not whether it is the parent
process of your program. You can determine if 4DOS is the parent
process by comparing the PSP value returned in CX to the PSP
chain pointer at offset 16h in your program's PSP.
4DOS also generates two different INT 2F calls to allow TSRs or
other programs to tell when 4DOS is at the prompt. These calls
have AX = D44Eh. The first occurs immediately before displaying the
prompt, with BX = 0; the second occurs after displaying the prompt
and immediately before accepting keyboard input, with BX =1. Any
routine intercepting these calls should preserve at least the SI,
DI, BP, SP, DS, ES, and SS registers.
You can put keystrokes into the KEYSTACK driver via the MS-DOS
IOCTL call. First, open the device 4DOSSTAK:
MOV AX,3D01h
DS:DX = pointer to the device name "4DOSSTAK"
INT 21h
The file handle will be returned in AX. Then send the string to
the KEYSTACK device driver:
MOV BX,AX
MOV AX,4403h
CX = string length
DS:DX = pointer to string
INT 21h
4DOS Reference Manual Copyright 1991, JP Software Inc. 149
Appendix E - Tips and Troubleshooting
This appendix covers general usage notes and troubleshooting
information about 4DOS. It will help you figure out what to do
if you're having trouble with 4DOS, or compatibility problems
with another software package.
What isn't covered here is information on compatibility with
specific hardware or individual software packages. Because this
information is subject to change as 4DOS and other programs are
modified, we have included it in the file COMPAT.DOC, which is
distributed with 4DOS. This file is updated with every new
release to reflect the latest compatibility information. It
should be read in conjunction with this appendix.
Installation and Boot
Most 4DOS installation problems occur because the instructions in
the manual have not been followed correctly. If you have
trouble, re-read the instructions carefully and see if they cover
the problem you're having. If not, try the information below.
If you have questions about booting 4DOS on a system attached to
a network, see the section in this appendix Using 4DOS on a
Network.
If you get a message such as "missing command interpreter" or
"can't find EXE file", you probably have the 4DOS files in the
wrong place. 4DOS is easiest to install when its system files
(KEYSTACK.SYS, 4DOS.COM, and 4DOS88.EXE or 4DOS286.EXE) are
stored in the root directory of your boot disk. If they aren't,
be sure the SHELL command in CONFIG.SYS has the correct drive and
path for 4DOS.COM, and that the /L: switch is set properly. Also
be sure that you are setting COMSPEC properly in AUTOEXEC.BAT, or
secondary shells won't load correctly.
If the system hangs after 4DOS is loaded (i.e., while processing
4START.BAT or AUTOEXEC.BAT), edit AUTOEXEC to remove the program
being loaded at the point where the hang occurs, and try again.
If problems are inconsistent or persist, edit CONFIG.SYS and
AUTOEXEC.BAT to remove all of the device drivers and TSRs that
you can reasonably remove and still have the system boot. Then
put them back one at a time until you find out what program or
combination of programs is causing the problem.
If you have trouble with keyboard device drivers or TSRs
(including those that use "hot keys"), try removing KEYSTACK.SYS
to see if there is a conflict between it and the other program.
If the KEYSTACK command fails to work, try loading it as late as
possible in CONFIG.SYS; another device driver may be stealing the
keyboard interrupt and failing to pass it along to KEYSTACK.
4DOS Reference Manual Copyright 1991, JP Software Inc. 150
If you have trouble booting 4DOS, or see garbage characters in
your environment immediately after boot, check the length of your
SHELL command. As discussed in Installation, the line may not
have more than 33 characters beyond the name of the shell
(including trailing spaces), due to a bug in all versions of MS-
DOS and PC-DOS.
AUTOEXEC and 4START Problems
If you follow the instructions in the manual, both of these files
should work with no trouble. Some common problems are:
1. AUTOEXEC.BAT is not executed when the primary shell is
started. This occurs because you did not put a /P in the SHELL
command, or the AUTOEXEC.BAT file is not in the root directory
of the boot drive.
2. AUTOEXEC.BAT is executed when a secondary shell is started.
You've put a call to AUTOEXEC.BAT into 4START, moved the
contents of AUTOEXEC.BAT into 4START, or called 4DOS with a /P
option on the command line. 4START should only be used for
commands to be executed when any shell is started. Commands
for the primary shell should go in AUTOEXEC.BAT.
3. 4START is not executed when a secondary shell is started.
This is because 4DOS cannot find 4START. 4START must be a
.BAT or .BTM file, located in the root directory of the drive
COMSPEC points to.
4DOS Reference Manual Copyright 1991, JP Software Inc. 151
Booting from a Floppy Disk
4DOS will boot properly from a floppy disk, as long as cautions
about file locations are observed carefully.
4DOS.COM, KEYSTACK.SYS, and 4DOSxx.EXE should be placed in the
root directory of the floppy disk, and the SHELL and DEVICE
commands should point to them. If your system has a hard disk,
the files can be placed there instead; be sure to set the /L:
switch so the 4DOS EXE file can be found.
When you boot from a floppy disk, 4DOS sets COMSPEC to point to
that disk (e.g. A:\4DOS.COM), regardless of where the 4DOS files
are loaded from (it isn't possible for the primary shell to
determine where it was loaded from and set COMSPEC accordingly).
If you are booting from a floppy disk on a system with a hard
disk, and you want secondary shells to load 4DOS from the hard
disk, you MUST set the COMSPEC yourself in AUTOEXEC.BAT to point
to the hard disk copy of 4DOS.
When using a pipe the temporary files created are written to the
root directory of the boot drive. If you are booting from a
floppy disk and want pipe temporary files to be written elsewhere
(e.g. to a hard disk), set the TMP environment variable to point
to the correct path. See Redirection in Using 4DOS for details
on pipes and TMP.
The AUTOEXEC and 4START batch files are always loaded from the
root directory of the boot drive when starting the primary shell,
so they will have to be on the floppy disk. The 4START file for
secondary shells is loaded from the root directory of the drive
COMSPEC points to, so if you are using 4START and change COMSPEC
be sure to make a copy of 4START on the new drive.
Hardware Errors
4DOS is compatible with virtually all PC hardware, including a
wide variety of systems, memory configurations, disk drives,
keyboards, and so on. While compatibility problems between 4DOS
and your hardware could occur, hardware problems which appear to
be due to 4DOS are usually found to be due to the hardware
itself, or to other software.
4DOS performs ALL disk I/O through standard MS-DOS calls. We
have avoided including capabilities which require direct access
to the disk , in order to maintain the maximum level of
compatibility with your disk hardware. There are no known
incompatibilities between 4DOS and disk drive hardware or
partitioning software. 4DOS is compatible with the large (over
32 MB) disk volumes created by Compaq DOS 3.31 and MS-DOS / PC-
DOS 4.0.
4DOS Reference Manual Copyright 1991, JP Software Inc. 152
If you find that you are having trouble with a disk drive while
running under 4DOS, check carefully to see what the problem is
and whether it can be reproduced under COMMAND.COM. There has
never been a documented instance of damage to a directory or FAT
due to a problem in 4DOS. When such problems occur it is
understandable that a new part of the operating system is the
first thing suspected of causing them, but in the few cases we
have heard about the problem has always turned out to be due to
hardware problems or errors in applications software.
Memory
4DOS does its best to detect and properly access all the types of
memory your PC can have: MS-DOS RAM, EMS, XMS, and extended
memory. 4DOS' access to these areas is always through standard
documented methods. If you want to know whether 4DOS sees your
system's memory accurately, check the output of the MEMORY
command.
Note that the output of MEMORY will show slightly more free MS-
DOS RAM than is shown by CHKDSK and some memory map programs.
This is because these programs do not count their own environment
space as free space. When 4DOS is running this space is not
occupied by a program's environment, and hence appears to be
free.
MEMORY's report of free space includes the space occupied by the
4DOS transient portion, at the end of MS-DOS memory (this space
is freed whenever an application is run). While 4DOS is running
this space is reserved, and is not available to 4DOS itself for
use by commands which allocate DOS memory (COPY, DIR, LIST,
SELECT, SETLOCAL, and the processing of .BTM files). If you use
one of these features and receive an "out of memory" error when
running in relatively limited (under 90K) memory (e.g., when
shelled to 4DOS from an application), the problem may be there is
not enough room for both 4DOS itself, and the memory to perform
the command, despite what appears to be a reasonable amount of
free RAM when looking at the output of MEMORY.
4DOS EMS swapping sometimes has difficulty with EMS drivers which
do not fully meet the EMS 3.2 specifications (4DOS supports, but
does not require, EMS 4.0). If you have trouble accessing EMS
for swapping, check COMPAT.DOC to see if there are any known
problems with your EMS board or the associated driver software.
4DOS Reference Manual Copyright 1991, JP Software Inc. 153
Critical Errors
A "critical" error is an error that gives you the "Abort, Retry,
Fail" message. When running 4DOS, this message appears as
follows:
[Error message]
R(etry), I(gnore), F(ail), or A(bort)?
The error message on the first line explains the error that has
occurred, and the device it occurred on. The second line prompts
for your choice of action (the Fail choice will not be displayed
under MS-DOS 2).
A critical error usually indicates a hardware malfunction. The
error may be that the device doesn't exist, there is no disk in
the drive, the network has gone down, or a data error occurred.
In most cases you will choose R to retry the operation, or A to
abort the operation. Choose I(gnore) at your peril: this
response will cause 4DOS to proceed as if the error had not
occurred!
F(ail) will tell 4DOS that the operation it was attempting has
failed, which will generally produce another error message. For
example, if you attempt to do a
directory on drive A with no disk in the drive, and answer F to
the resulting critical error, you will get an additional error
message, "Invalid drive A".
Many programs install their own critical error handlers. If you
get a critical error message within an application and the second
line does not read as shown above, the message probably did not
come from 4DOS, and any problem in handling your response
properly is due to the application, and not to 4DOS.
Choosing A to abort within an application may abort the entire
application, and not just the operation being performed,
depending on which critical error handler is in use (4DOS' or the
applications's), and how the application's critical error handler
(if any) is designed.
4DOS Reference Manual Copyright 1991, JP Software Inc. 154
Video
4DOS is compatible with most display adapters and monitors.
However as with any software package, you may have to configure
4DOS to run properly on your system.
4DOS uses two methods of displaying text on the screen:
1. Prompts and normal messages call DOS to write text to the
screen. If you use an ANSI driver, it will process these
calls. Otherwise, DOS will transmit the text to the BIOS (the
I/O software which comes on your system or video board) to
display it on your screen. This method for displaying text
will work on all MS-DOS systems, regardless of video type.
2. The DRAWBOX, DRAWHLINE, DRAWVLINE, LIST, SELECT, and SCRPUT
commands bypass MS-DOS, the BIOS, and ANSI, and write text
directly to video memory. These commands will only work on
systems with 100% PC-compatible video. On other systems,
results will be unpredictable at best. If you have such a
system, you probably know it already, as most PC applications
will have similar problems.
Video Cursor
The video cursor shape is defined by "start" and "stop" line
numbers within a character "cell" (the space occupied by one
character on the screen). Typical cell sizes are 14 lines on a
monochrome or EGA system, and 8 lines on a CGA system; other
video cards will have varying cell sizes.
4DOS reads the cursor shape at boot, and defines that as the
default shape. The shape used by 4DOS can be adjusted with
SETDOS /Sb:e, where b is the beginning line and e is the ending
line. To see what values 4DOS is using, run SETDOS with no
parameters. The shape defined in SETDOS is used for the default
editing mode (set by SETDOS /M). The "other" editing mode (e.g.,
if overstrike is the default then insert is the other mode) uses
a cursor that starts at line 0 and ends on the same line as the
default cursor.
If you have trouble with the cursor, experiment with the SETDOS
/S command until you find a setting that works for your system.
Note that you will have to reduce the SETDOS cursor settings if
you switch an EGA or VGA to 43-line or 50-line mode. The cursor
lines in 25-line mode use a larger character cell, and lie
outside the smaller 43-line or 50-line cell, making the cursor
invisible.
If you find the cursor has disappeared and the problem is not
addressed by SETDOS /S, it is probably due to screen color
problems. The cursor is shown in the color of the underlying
4DOS Reference Manual Copyright 1991, JP Software Inc. 155
character cell. If that cell has (for example) the color
attributes of black on black, the cursor will be invisible. If
you have an ANSI driver installed, you can test this out easily
by clearing the screen to a known color (see CLS in the Command
Reference Guide). The cursor should reappear. If the problem
persists, you will need to determine what is setting your screen
attributes to an invisible color. One common source of this
problem is use of an ANSI driver for 43-line or 50-line mode on
an EGA/VGA system when the ANSI driver does not support these
modes.
Screen Length
The SETDOS /R command sets the 4DOS screen length. It will not
cause 4DOS to attempt to change the video mode; it is an internal
variable used to determine display length for LIST, SELECT, and
those commands which have a "pause" option (TYPE /P, DIR /P,
etc.). 4DOS normally determines the screen length from the BIOS.
If you have a non-standard display and/or have trouble with the
default screen length, try correcting it with SETDOS /R.
SETDOS /R will NOT affect display scrolling at the command
prompt. This scrolling is handled by ANSI and/or your system
BIOS. If you have an EGA or VGA, and have put the screen in 43-
line or 50-line mode, you may find that the display still scrolls
at the 25th line. This is usually because your ANSI driver is
not properly supporting the extended screen length; it is not a
4DOS problem.
ANSI.SYS
ANSI.SYS is a device driver, normally installed in your
CONFIG.SYS file, which allows control of a variety of screen
characteristics via strings of characters sent to the screen.
Most versions of MS-DOS include a copy of ANSI.SYS, and there are
a number of more powerful versions available as public-domain,
shareware, or retail products.
The only 4DOS commands requiring ANSI.SYS are CLS and COLOR. CLS
will always clear the screen, but will ignore color
specifications if ANSI.SYS is not installed. COLOR will work
ONLY if you have an ANSI driver installed.
4DOS normally detects automatically whether an ANSI driver is
installed. If you have ANSI installed and 4DOS doesn't seem to
recognize it (e.g., CLS BRIGHT WHITE ON BLUE still leaves the
screen in white on black), try SETDOS /A1, which forces 4DOS to
use ANSI commands.
4DOS Reference Manual Copyright 1991, JP Software Inc. 156
4DOS and COMMAND.COM
4DOS is designed to be 99% compatible with the standard MS-DOS
command interpreter, COMMAND.COM. In virtually all cases
commands will work identically under 4DOS and COMMAND.COM.
However, 4DOS has improved on COMMAND.COM in a number of areas,
and on rare occasions these improvements produce a conflict.
In some cases 4DOS command output differs from COMMAND.COM in
order to provide enhancements. For example, the default DIR
display is in alphabetical order, rather than physical order as
in COMMAND.COM. The filenames are also in lower case, rather
than upper case. With DIR, as in most such cases, command
options allow you to specify output that is closer to or exactly
the same as COMMAND.COM.
COMMAND.COM also contains bugs or quirks which are not part of
its documented behavior, and some programmers and users have
chosen to rely on these bugs and quirks in writing their batch
files and programs. 4DOS does not emulate some of these quirks -
in some cases to do so would be wrong; in others it would hinder
useful features of 4DOS.
The only specific compatibility difference we are aware of
between 4DOS and COMMAND.COM that is unrelated to undocumented
"features" is in handling batch file variables. 4DOS allows 128
batch variables (%0 to %127), and COMMAND.COM only 10 (%0 to %9).
COMMAND.COM therefore only considers the first digit after the
"%" as part of the variable name. As a result, a string like
"%10A" will be interpreted by 4DOS as "the value of batch
variable 10, followed by the character A", and by COMMAND.COM as
"the value of batch variable 1, followed by the characters 0A".
However, you can force 4DOS to make the same interpretation as
COMMAND.COM by using the "%[varname]" feature: the string
"%[1]0A" will be interpreted the same way COMMAND.COM interprets
"%10A".
Some users have renamed 4DOS.COM to COMMAND.COM. This will work
provided you set COMSPEC properly (see Installation), and may be
necessary to deal with programs that ignore COMSPEC and call
COMMAND.COM directly. However, we do NOT recommend this approach
under most circumstances. It will cause the DOS FORMAT /S
command to copy 4DOS.COM rather than COMMAND.COM when creating a
bootable floppy disk. Such a disk will not in fact be bootable
because the 4DOS EXE file will not be on it, and you may not want
it to boot with 4DOS in any case. It may also lead to confusion
when someone else looks at your disk and sees a file called
COMMAND.COM that isn't really COMMAND.COM.
4DOS Reference Manual Copyright 1991, JP Software Inc. 157
Using 4DOS on a Network
4DOS is compatible with most MS-DOS-compatible networks. This
section will give you some tips on using 4DOS properly on a
network, and on the locations used for 4DOS files on a network.
If you need to boot from a network drive (i.e., on a diskless
workstation), you must have the network drive accessible at boot
time. If this condition is satisfied (so 4DOS can find its files
on the network drives), the standard options can be used to load
4DOS from the network drive.
When using 4DOS on a network, you must pay careful attention to
where files are stored in order to be sure that two 4DOS users do
not attempt to access the same file at the same time. When
swapping to disk (either explicitly with the /S:D option, or
implicitly because best guess swapping is used and no EMS or XMS
is available), you must be sure that no two users ever use the
same directory for their disk swap files, since the filenames
(4DOSSWAP.000, .001, etc.) will conflict. This includes swap
files created by shelling to 4DOS from a program, or running
secondary shells implicitly (e.g. with a MAKE utility). Set the
swap file location explicitly with the /S option, assigning each
user's swap files to a different directory on the network drive.
The primary shell's swap file location is controlled by the /S
option in CONFIG.SYS. For instance, the following command will
boot 4DOS with best guess swapping and store any disk swap file
created in directory F:\USERA:
shell=c:\ /s:bf:\usera
The swap file location for secondary shells is controlled by the
4DSHELL environment variable (see Installation). Using the above
example, the appropriate setting for 4DSHELL would be:
set 4dshell=/s:bf:\usera
Both SHELL and 4DSHELL must be set properly to ensure that there
are no problems with disk swap files on your network. Note that
if you set up the SHELL command and 4DSHELL to force EMS or XMS
swapping (/S:E or /S:X), there is no need to set up a separate
directory for each user for this purpose as there will be no disk
swap files.
Pipes are methods of passing information from one program to
another, and are invoked with the pipe symbol | on the command
line (see I/O Redirection in Using 4DOS). Pipes work by taking
the output from one program, storing it in a temporary file, then
telling a second program to obtain its input from that file. The
temporary files, named P.1$$ and P.2$$, are placed by default in
the root directory of the boot drive, but can be placed on a
different drive and directory by setting the TMP environment
variable.
4DOS Reference Manual Copyright 1991, JP Software Inc. 158
If you choose to set TMP, or if you have a system where multiple
users can boot from the same directory, the same cautions given
for disk swapping must be followed for pipe temporary files; that
is, you must ensure that each user's pipe temporary files go to a
separate directory. For example, for the user in the examples
for disk swapping above, the pipe temporary files can be set to
go the same directory by placing this command in AUTOEXEC.BAT:
set tmp=f:\usera
Common Questions and Problems
This section covers a variety of problems and questions which
come up regularly in technical support calls and messages, and
which are not covered by the sections above. If you have
questions about compatibility with a specific software product,
refer to COMPAT.DOC.
When you find another piece of software that appears to be
incompatible with 4DOS, there are several techniques you can try
to determine where the problem lies. Even if these methods are
not workable as a permanent solution, they will provide valuable
information as to the nature of the problem.
Try removing all of the device drivers and TSRs you can from
CONFIG.SYS and AUTOEXEC.BAT (including KEYSTACK.SYS), and see if
the problem persists. If it doesn't, put the drivers and TSRs
back one at a time until you find the conflict. Many apparent
two-way compatibility problems ("4DOS and package X don't work
together") turn out to be three-way interactions between 4DOS,
the problem program, and a device driver or TSR.
If the program you are having trouble with uses EMS memory and
you are using EMS swapping, you can try changing to disk swapping
to see if the problem goes away. The same is true for XMS
swapping and programs which use XMS.
If you are using the /U option on a system with XMS memory, try
removing it to see if the program cannot work when the command
processor is loaded high.
If the program is not a TSR, try running it under COMMAND.COM.
For example, if COMMAND.COM is in C:\:
c:\command /c myprog [parameters]
If you need to continue to use this method, you can define an
alias:
alias myprog `c:\command /c myprog %&`
If the program is large enough to overwrite the transient portion
of COMMAND.COM, you will need to change COMSPEC temporarily to
4DOS Reference Manual Copyright 1991, JP Software Inc. 159
point to COMMAND.COM, to avoid an error message when exiting the
program.
Problems with Shelling to DOS
Many application programs allow you to "shell to DOS" from inside
the program. If you have trouble shelling to DOS, or running a
program which uses an implicit shell (e.g., a hard disk manager
which shells to DOS to perform file copies), check your COMSPEC
and 4DSHELL settings. To shell to 4DOS, COMSPEC must point to
4DOS.COM, and the 4DOS EXE file must be in the same directory
that COMSPEC points to, or if it is not, the /L: switch must be
set in 4DSHELL. (See Installation for more details on COMSPEC
and 4DSHELL.) You can view the settings of these variables with
the command SET /P; this is a more reliable approach than looking
at AUTOEXEC, since it tells you what the variables are really set
to, instead of what you tried to set them to.
You can test whether these variables are set up properly by
changing to the directory you are in when the problem occurs, and
entering %COMSPEC at the prompt. This will attempt to execute
the program COMSPEC points to. If this works and 4DOS starts,
type EXIT to return to the previous shell. If it fails, correct
COMSPEC and/or 4DSHELL.
If COMSPEC and 4DSHELL are set correctly and you still cannot
shell to DOS, you may have too little memory. Try running a
smaller application which also shells to DOS and verify that it
works correctly; if so, see if the problem application can be
adjusted to provide more free memory for a DOS shell.
Finally, you may have trouble shelling to DOS because the
application is trying to shell directly to COMMAND.COM, rather
than looking at the COMSPEC setting. If you have moved
COMMAND.COM or changed your PATH since you installed 4DOS, make
sure there is a copy of COMMAND.COM accessible to the program and
see if it will then shell properly. You may need to contact the
program manufacturer to determine if a particular program shells
directly to COMMAND.COM.
4DOS Reference Manual Copyright 1991, JP Software Inc. 160
Name Conflicts with 4DOS Commands
You may have a program which has the same name as a 4DOS internal
command. Many 4DOS users use Vern Buerg's excellent file viewer,
LIST.COM, whose name conflicts with 4DOS' internal LIST command.
Such conflicts can be solved in one of two ways. If you want to
disable the 4DOS internal command entirely, use the SETDOS /I-
command. For example:
setdos /i-LIST
The command can be re-enabled with SETDOS /I+ (see SETDOS in the
Command Reference Guide).
The other method is to set up an alias to redirect the command to
the external program. For example:
alias list c:\util\list.com
This also disables the internal command. However you can then
add another alias to invoke the internal command under a
different name. For example:
alias show *list
Problems with Memory-Resident Programs (TSRs)
Most TSRs will work properly with 4DOS. If you have trouble
getting a TSR to pop up, you may need to use the SETDOS /L1
command to convince the TSR that it is at the DOS prompt, or
because it traps the DOS line input interrupt to do some of its
work.
If you have trouble getting a TSR to unload, the problem may be
due to the method used by the TSR to remove itself from memory.
In most cases programs which cannot be unloaded directly can be
removed using the MARK and RELEASE utilities available from
TurboPower Software. These programs are part of a package called
TSRCOM which also contains many other useful utilities, and is
available free on many bulletin boards and on-line services, and
is included on the 4DOS Utility Disk available from JP
Software.
4DOS Reference Manual Copyright 1991, JP Software Inc. 161
Glossary
4DSHELL: An environment variable which defines the 4DOS switch
values for secondary shells.
4START: A batch file which is executed whenever 4DOS is started,
either as a primary shell or a secondary shell.
Alias: A shorthand name for a command or series of commands.
Alias Argument: A numeric variable included in an alias
definition, allowing a different value to be used in the alias
each time it is executed.
ANSI.SYS: A device driver supplied with MS-DOS which provides
enhanced screen display and keyboard macros, or one of the many
similar programs available free or as shareware or retail
products.
Append: Concatenation of one file or string onto the end of
another. (There is also an MS-DOS external command, APPEND,
which has an entirely different meaning -- and should be used
extreme with caution!)
Application: A program run from the command prompt or a batch
file. The term is used broadly to mean any program other than
the command processor; and more narrowly to mean a program with a
specific purpose such as a spreadsheet or word processing
program, as opposed to a utility.
Archive: A file attribute indicating that the file has been
modified since the last backup (presuming that the last backup
cleared the archive attribute, as most backup programs do). Also
sometimes used to refer to a single file which contains a number
of other files in compressed form.
Argument: A piece of additional information placed after a
command or function name. For example in the command DIR XYZ,
XYZ is an argument. Also used to refer to an alias argument or
batch file argument.
ASCII: The American Standard Code for Information Interchange,
which defines numeric values for 128 different characters
comprising the English alphabet, numbers, punctuation, and some
control characters.
ASCII File: A file containing ASCII text, as opposed to a binary
file which may contain codes, numbers, or other information that
cannot be sensibly interpreted as text.
4DOS Reference Manual Copyright 1991, JP Software Inc. 162
Attribute: A characteristic of a file which can be set or
cleared. The standard attributes are Read-Only, Hidden, System,
and Archive. The special attributes Volume Label and Directory
are also used for files of those types.
AUTOEXEC.BAT: A batch file which is AUTOmatically EXECuted when
the computer is started.
BAT File: Same as a Batch File.
Batch File: A text file containing a sequence of MS-DOS or 4DOS
commands. Batch files are used to save command sequences so that
they can be re-executed at any time, transferred to another
system, etc.
Batch File Argument: A numeric variable used within a batch
file, allowing a different value to be used at that spot in the
file each time it is executed.
Binary File: A file containing information which does not
represent or cannot sensibly be interpreted as text. See also
ASCII File.
Block Device: A physical device for input or output which can
transmit or receive large blocks of data while the computer is
engaged in other activities. Examples include disk, tape, and
CD-ROM drives, and many networks.
Boot: The process of starting the computer and loading MS-DOS
and the command processor into memory.
Boot Directory: The current directory at the time the system is
booted, almost always the root directory of the boot drive.
Boot Drive: The disk drive that the system is booted from,
usually A: (the floppy disk) or C: (the hard disk).
Break: A signal sent to a program (including 4DOS) to tell it to
halt what it is doing. The Ctrl-C key or Ctrl-Break key is used
to send this signal. Some external commands abort when they
receive a break signal; others return to a previous screen or
menu, or abort the current operation .
BTM File: A special type of batch file which is loaded into
memory, dramatically speeding up execution.
Buffer: An area of memory set aside for storage. Usually refers
to disk buffers, used to save information as it is transferred
between your program and the disk; or to the keyboard buffer.
4DOS Reference Manual Copyright 1991, JP Software Inc. 163
Character Device: A physical device for input or output which
must communicate with your computer one character at a time.
Examples include the console, communications ports, and printers.
Code Page: A set of definitions which tells DOS how to get and
display date, time, and other information in the format
appropriate to a particular country.
Command Completion: A 4DOS feature which allows you to recall a
previous command by typing the first few letters of the command,
then an up-arrow or down-arrow.
Command Echoing: A feature which displays commands as they are
executed. Echoing can be turned on and off.
Command History: A 4DOS feature which retains commands you have
previously executed, so that they can be modified and re-executed
later.
Command Processor: A program, such as 4DOS or COMMAND.COM, which
interprets commands and executes other programs. The command
processor is the first program loaded when the system is booted.
Command Recall: See Command History.
Command Tail: The portion of a command consisting of all the
arguments, i.e. everything but the command name itself.
Compound Command: See Multiple Commands.
COMSPEC: An environment variable which defines where to get the
command processor for a secondary shell.
Conditional Commands: A 4DOS feature allowing commands to be
executed or skipped depending on the results of a previous
command. See also Exit Code.
CONFIG.SYS: A file which tells MS-DOS what device drivers to
install, what command processor to use, and other information
about what to do when your system boots. See your MS-DOS manual
for more information.
Console: A term describing the PC keyboard and display,.
4DOS Reference Manual Copyright 1991, JP Software Inc. 164
Control Character: A character which is part of the ASCII code,
but does not have a normal text representation, and which can be
generated by pressing the Ctrl key along with another key. For
example the control character called "BEL" is generated by
pressing Ctrl-G, and will cause the computer to beep if pressed
at the MS-DOS prompt.
Country Code: See Code Page.
CR: The ASCII character "carriage return", generated by pressing
the "Enter" key on the keyboard, and stored in most ASCII files
at the end of each line.
Critical Error: An error, usually related to input, output, or
network access, which prevents a program from continuing. When a
critical error occurs a prompt such as "R(etry), I(gnore),
F(ail), or A(bort)" is given and you must decide what action to
take.
Current Directory: The directory in which all file operations
will take place unless otherwise specified. For example if the
current directory is C:\MYFILES then the command "DEL XYZ" will
delete the file XYZ in the directory C:\MYFILES, and will not
affect other files with the same name which may be in other
directories.
Description: A string of up to 40 characters assigned to
describe a file with the 4DOS DESCRIBE command.
Device: A physical device for input or output such as the
console, a communications port, or a printer. Sometimes the term
"device" alone is used to refer to character devices such as
those listed above, and excludes block devices.
Device Driver: A program which allows DOS to communicate with a
device, and which is loaded into memory when the system is
booted, via a statement in CONFIG.SYS. Some device drivers are
used to manage memory or for other similar internal functions,
rather than to communicate with an external device.
Directory: A portion of any disk, identified by a name and a
relationship to other directories in a "tree" structure, with the
tree starting at the root directory. A directory separates files
on the disk into logical groups, but does not represent a
physical division of the data on the disk.
Disk Swapping: A type of swapping where the transient portion of
4DOS is stored on disk while an application is running.
4DOS Reference Manual Copyright 1991, JP Software Inc. 165
DOS Memory: The portion of your computer's memory available for
use by DOS, the command processor, and application programs. On
most PCs this area consists of the first 640K bytes of the
computer's memory (one K is 1024 bytes).
Echo: See Command Echoing.
EMS Memory: Memory which conforms to the Lotus - Intel -
Microsoft Expanded Memory Specification (LIM EMS). This
hardware/software standard allows programs to access large
amounts of memory outside of standard DOS memory or extended
memory. Most systems which have EMS memory have either a
specific EMS board (on any PC or compatible system), EMS
emulation software (on PC-AT compatible systems), or a 386
control program such as QEMM or 386MAX (on 386 systems). If you
do not have one of these items, you probably do not have EMS
memory.
EMS Swapping: A type of swapping where the transient portion of
4DOS is stored in EMS memory while an application is running.
Environment: An area of memory which contains multiple entries
in the form "NAME=value". Each entry is called an environment
variable, with the name "NAME". See also master environment and
passed environment.
Environment Variable: The name of a single entry in the
environment. Environment variables are entered with the SET
command, and used to associate the specified value with the
specified name for any purpose desired by the user. Typically,
their function is to set default switches for a program, specify
a directory path where files can be found, and so on. When 4DOS
encounters an environment variable name in a command in the form
"%NAME" (or "%NAME%"), it substitutes the corresponding value in
its place.
Errorlevel: A numeric value returned from an external command to
indicate its result (e.g. success, failure, response to a
question), and accessible via the IF ERRORLEVEL command and the
%? environment variable. The value is between 0 and 255, plus
256 if the program was interrupted by a break, 512 if it aborted
due to a critical error, or 768 if it remained resident in memory
as a TSR. See also Exit Code.
Escape Character: This term has two meanings. In some contexts
it means the 4DOS escape character, normally Ctrl-X, which is
used to suppress the normal meaning of or give special meaning to
the following character. In other cases it refers to the
specific ASCII character ESC. The meaning must be determined
from the context.
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Executable Extensions: A 4DOS feature which allows you to
specify the application to be executed when a file with a
particular extension is named at the command prompt.
Executable File: A file with the extension .COM or .EXE, which
can be loaded into memory and run as a program.
Exit Code: The error level returned by an external command, or a
similar exit code returned by a 4DOS internal command. 4DOS
internal commands return an exit code of 0 if successful, or non-
zero if unsuccessful.
Expansion: The process 4DOS goes through when it scans a command
line and substitutes the appropriate actual values for aliases,
alias arguments, batch file arguments, and environment variables.
Extended ASCII Character: A character which is not part of the
standard set of 128 ASCII characters, but is used on the PC as
part of an extended set of 256 characters. These characters
include international language symbols, and box and line drawing
characters.
Extended Memory: Any memory on a 286-based (PC-AT compatible) or
386-based computer system which is above the 1 MB (one megabyte,
or 1024*1024 bytes) of memory that DOS can address directly. Any
PC-AT compatible or 386 system with more than 640K of memory has
extended memory. This memory can be used for a variety of
purposes depending on the software installed to utilize it. See
also XMS.
External Command: A program which resides in an executable file,
as opposed to an internal command which is part of the command
processor. For example, FORMAT and DISKCOPY are external
commands; you can find them on your DOS disk under the names
FORMAT.COM and DISKCOPY.COM.
File Attribute: See Attribute.
File Description: See Description.
Filename Completion: A 4DOS feature which allows you to type
part of a filename on the command line, and have 4DOS fill in the
rest for you.
Free Memory: Usually, the amount of DOS memory which is
currently unoccupied and available for use by applications.
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Hidden: A file attribute indicating that the file should not be
displayed with a normal DIR command, and should not be available
for access by programs unless they specifically request use of
hidden files.
History: See Command History.
Insert Mode: When editing text, a mode in which newly typed
characters are inserted into the line at the cursor position,
rather than overwriting existing characters on the line. See
also overstrike mode.
Internal Command: A command which is part of the command
processor, as opposed to an external command. For example, DIR
and COPY are internal commands.
Keyboard Buffer: A buffer which holds keystrokes you have typed
that have not yet been used by the currently executing program.
Label: A marker in a batch file which allows GOTO or GOSUB
commands elsewhere in the batch file to "jump" to the command on
the line following the label. See also Volume Label.
LF: The ASCII character "line feed", not usually generated from
the keyboard, but stored in most ASCII files at the end of each
line after the CR character.
Master Environment: The master copy of the environment
maintained by the command processor. The master environment is
manipulated with the SET and UNSET commands. The size of the
master environment is set by the /E: command line switch.
Memory Resident Mode: A method of installing 4DOS where swapping
is disabled, and all of 4DOS remains permanently resident in
memory. Memory-resident mode requires much more memory than the
normal swapping mode.
Multiple Commands: A 4DOS feature which allows multiple commands
to be placed on a line, separated by a caret (^) or other user-
defined character.
Multitasking: A capability of some software (and the related
hardware) which allows two or more programs to run apparently
simultaneously on the same computer. Multitasking software for
PC compatible systems includes programs like DESQview.
Option: See Switch.
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Overstrike Mode: When editing text, a mode in which newly typed
characters overwrite existing characters on the line, rather than
being inserted into the line at the cursor position. See also
Insert Mode.
Parameter: See Argument.
Parsing: The process 4DOS performs when it analyzes the command
line, performs alias and environment variable expansion, and
finds the appropriate internal command or external command to
execute.
Passed Environment: A copy of the master environment created
before running an application, so that any changes made by the
application will not affect the master environment. The size of
the passed environment is determined by the amount of space
actually used in the master environment when the application is
started.
Path: A specification of the directories a file resides in,
including all parent directories. For example, the path for
C:\WPFILES\MYDIR\MEMO.TXT is C:\WPFILES\MYDIR\. Also used to
refer to the environment variable PATH, which contains a series
of path specifications used when searching for external commands
and batch files.
Pipe: A method for collecting the standard output of one program
and passing it on as the standard input of the next program to be
executed, signified by a vertical bar "|" on the command line.
See also Redirection.
Primary Shell: The copy of the command processor which is loaded
when the system boots.
RAM Disk: A pseudo "disk drive", created by software, which
appears like a normal physical disk drive to programs. RAM disks
can be stored in extended memory, XMS memory, EMS memory, or DOS
memory, and provide a convenient way for programs to use this
memory for temporary files.
Read-Only: A file attribute indicating that the file can be
read, but not written by MS-DOS and 4DOS.
Reboot: The process of restarting the computer, usually by
pressing the Ctrl, Alt, and Del keys simultaneously.
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Redirection: A method for collecting the standard output of a
program in a file, and/or of providing the standard input for a
program from a file, signified respectively by a greater than
symbol ">" or less than symbol "<" on the command line. See also
Pipe.
Replaceable Parameter: See Alias Argument and Batch File
Argument.
Resident Portion: The small portion of 4DOS stored permanently
in memory when swapping mode is in use, as opposed to the larger
transient portion. The resident portion is stored as close as
possible to the beginning of DOS memory.
Root Directory: The first directory, from which all other
directories are "descended." The root directory is referenced
with a single backslash (\). When a disk is first formatted, it
is the only directory.
Secondary Shell: Any copy of any command processor which is
loaded after the system boots. Secondary shells may be started
from the command line; by executing a "shell to DOS" operation
from within an application; implicitly by executing some MS-DOS-
related functions within certain applications; or by starting a
new partition in a multi-tasking or task switching system.
Shell: A command processor. Also used to refer to a program
which gives access to MS-DOS functions and commands through a
menu- or mouse-driven system.
Source: In the 4DOS file commands (COPY, MOVE, and RENAME), the
original files before any copying or modification has taken
place, i.e. those specified earlier on the command line. See
also Target.
Stack: An area of memory used by any program to store temporary
data while the program is running; more generally, any such
storage area where the last item stored is normally the first one
removed.
Standard Error: A file or character device where error messages
from a program are displayed. Standard error output always goes
to the console, unless redirection is used.
Standard Input: A file or character device where a program
obtains its normal input. Standard input always comes from the
console, unless redirection is used.
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Standard Output: A file or character device where normal output
from a program is displayed. Standard output always goes to the
console, unless redirection is used.
Subdirectory: Any directory other than the root directory. See
also Root Directory.
Swap File: A disk file created by 4DOS to store its transient
portion when disk swapping is in use.
Swapping: A 4DOS feature which removes the larger transient
portion of 4DOS from DOS memory while an application is running,
leaving the maximum possible amount of memory for the
application, yet allowing 4DOS to retain information such as the
command history after the application is finished. See also XMS
Swapping, EMS Swapping, and Disk Swapping.
Switch: An argument to an internal command or application which
specifies a particular behavior or setting. For example, the
command "DIR /P" might be referred to as "having the /P switch
set". Also, a configuration value for 4DOS specified on the
SHELL= line in CONFIG.SYS, or in 4DSHELL.
System: A file attribute indicating that the file belongs to MS-
DOS and should not be accessed by normal programs.
Target: In the 4DOS file commands (COPY, MOVE, and RENAME), the
final files after any copying or modification has taken place;
generally those referred to by the last specification on the
command line. See also Source.
Transient Portion: The larger portion of 4DOS stored in memory
temporarily when swapping mode is in use, as opposed to the
smaller resident portion. The transient portion is stored as
close as possible to the end of DOS memory, and is removed from
memory whenever an application is executed.
TSR: A Terminate and Stay Resident program, i.e. a program which
"terminates" but remains resident in DOS memory, to provide
capabilities such as network support, a pop-up notepad or
telephone dialer, a disk cache, or mouse support.
UMB: An XMS Upper Memory Block, whose address is above the end
of normal DOS memory, but is within the 1 megabyte of memory that
DOS can address directly.
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Variable: See Alias Argument, Batch File Argument, and
Environment Variable.
Volume Label: A special, hidden file placed on any disk whose
name constitutes a "label" for the entire disk.
White Space Character: Generally, a character used to separate
arguments on the command line. The white space characters
recognized by 4DOS are the space, tab, comma, semicolon, and
equals sign.
Wildcard: A character ("*" or "?") used in a filename to specify
the possibility that any single character ("?") or sequence of
characters ("*") can occur at that point in the actual name.
XMS Memory: A software method for accessing extended memory on
286 and 386 systems (and some systems which support version 4.0
of the EMS memory specification). XMS memory is not additional
memory, but is a software specification only. Its use generally
requires Microsoft's HIMEM.SYS be installed as a device driver,
or that another program such as 386MAX or MOVE-EM be used.
XMS Swapping: A type of swapping where the transient portion of
4DOS is stored in XMS memory while an application is running.
4DOS Reference Manual Copyright 1991, JP Software Inc. 172
Index
4DOS Cancel batch job 34
Features 1 CD 57
Memory Usage 18 CDD 58
Startup Options 21 CHCP 59
Swapping mode 22 CHDIR 57
4DOS.COM 9 CLS 60
4DOS.DOC 10 CMDLINE 3, 40
4DOS286.EXE 9 Code page 59
4DOS88.EXE 9 COLOR 61
4DOSSTAK 149 Colors 60, 114
4DSHELL 15, 25, 160 Command
4START 25, 27, 119, 151 Completion 29
Echoing 32
? 48 History and Recall 29
Line 3
ALIAS 35, 49 Line arguments 32
Alias Line editing 28
Expansion 35 Parsing 45
List 130 Processor 80
List size 21, 99 Reference Guide 46
Parameters 36 Separator 30, 119
Aliases 3, 10, 35, 37, 78, Syntax 47
130 COMMAND.COM 26, 157
AND 30 Comment 110
ANSI 60, 61, 119, 156 COMPAT.DOC 10
Append 62 Compatibility 10
Archive attribute 52, 62 COMPOUND 30, 119
Argument quoting 32 COMSPEC 15, 160
ASP 146 Conditional commands 3, 30
Association of Shareware Conditional execution 88, 91
Professionals 146 CONFIG.SYS 14, 19
ATTRIB 52, 89 Configuration 17
Attribute 52 Console 64
AUTOEXEC.BAT 14, 25, 27, 151 COPY 62
Automatic Installation 13 Country code 65
Create subdirectories 98
Batch Critical errors 154
File nesting 55 CTTY 64
File echoing 76 Current directory 57, 107, 109
File parameters 123 Cursor 113, 121, 155
File processing 56 File variables 34 DATE 65
Files 33 DEL 66
Processor 7 DELAY 67
Variables 157 DESCRIBE 68
BEEP 53 DESCRIPT.ION 68
Box 73 DIR 69
BREAK 54 Directory stack 72, 107
DIRS 72
CALL 55 Disk swapping 22
CANCEL 56, 108 Disk write verification 133
4DOS Reference Manual Copyright 1991, JP Software Inc. 173
DOS Shells 14 EXTENDED 89
DOS.HLP 10 Extended key codes 148
DOSMEM 89 Extended memory 99
DRAWBOX 73 External command 102
DRAWHLINE 74
DRAWVLINE 75 F1 28, 95
F8, F9 & F10 28, 30
ECHO 32, 76 File descriptions 2, 68
Edit 78 File attributes 52
EGA 156 Filename completion 30
ELSE[IFF] 91 Floppy disk 152
EMS 18, 89 FOR 81
Swapping 23, 153 FREE 82
ENDIFF 91 Frequency 53
ENDLOCAL 77, 122
ENDTEXT 126 GE 88
Environment 2, 131 GLOBAL 83
Size 2, 21 GOSUB 84, 112
Space 99 GOTO 85
Variables 2, 40, 78, 92, GT 88
93, 117, 122
@ext 42 Hardware errors 152
@full 42 HELP 10, 11, 86
@length[string] 42 Hidden attribute 52, 79
@name 42 HISTORY 87, 119
@path 42 History list 29, 87
@search 42 History size 22
@substr 42 Horizontal line 74
_BG 41
_CPU 41 I/O Redirection 43
_CWD 41 IF 88
_CWDS 41 IFF 91
_CWP 41 INKEY 92, 148
_CWPS 41 INPUT 93
_DATE 41 INSTALL 13
_DISK 41 INSTALL.BAT 9
_DOSVER 41 Installation 9, 150
_FG 41 INTERNAL 120
_SHELL 41 ISALIAS 89
_TIME 42 ISDIR 90
EQ 88
ERASE 66 Key Codes 148
Error messages 136 KEYSTACK 10, 11, 39, 94,
ERRORLEVEL 30, 41, 89 148, 149
ESCAPE 31, 119
Escape character 31, 119 Label 85, 134
ESET 78 Language support 59
EXCEPT 79 LE 88
Executable extensions 37 LINE 120
EXIST 89 Line editing mode 120
EXIT 80 LIST 95
Exit code 30 LOG 97
Expanded memory 99 LT 88
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Manual Installation 17 SCREEN 113
MARK 161 Screen length 156
MD 98 SCRPUT 114
MEMORY 99, 153 SELECT 115
Memory resident mode 18,23 SET 40, 117
Memory-resident programs 161 SETDOS 29, 30, 31, 32, 43,
MKDIR 98 76, 87, 110, 119,
MODE 120 155, 156, 161
MONITOR 90 SETLOCAL 77, 122
MOVE 100 SHAPE 121
Multiple arguments 4 Shell 14, 19, 21
Multiple commands 2, 30 Shelling to DOS 160
SHIFT 34, 123
Name conflicts 161 Standard
NE 88 Error 43
Network 3, 158 Input 43, 64, 125, 135
NOCLOBBER 43, 120 Output 43, 64, 125, 135
Starting 4DOS 27
OR 30 Stopwatch 128
OS/2 DOS box 1, 20 Subdirectory 98, 109
Subroutine 84, 112
Parent directory 109 SWAPPING 124
PATH 40, 98, 102 Swapping mode 18
PAUSE 103 System attribute 52
Pipes 44, 125,158
PKUNZIP 10, 11 TEE 125
POPD 104 TEXT 1 26
Primary shell 14 THEN 91
Programming for 4DOS 149 TIME 127
PROMPT 105 TIMER 128
PUSHD 107 Tips 150
TMP 41, 44, 159
Quick Start 12 Transient portion 18, 124
QUIT 108 Troubleshooting 150
Quotes 32 TSR 161
TSRCOM 161
RAM 99 TYPE 129
RD 109
Read-only attribute 52 UMB 23
README.DOC 10 UNALIAS 35, 50, 130
Redirection 3, 120 UNSET 131
RELEASE 161 UPPER 121
REM 110 Using 4DOS 27
REN 111
RENAME 111 Variable functions 42
Replaceable parameters 36 Variables 131
Resident portion 18 VER 132
RETURN 84, 112 VERBOSE 32, 76, 110, 121
RMDIR 109 VERIFY 63, 133
Root directory 98, 109 Version number 132
Root shell 14 Vertical line 75
ROWS 120 VGA 156
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VIDEO 90, 155
Video cursor 155
VOL 134
Volume label 134
Wildcards 2
XMS 18, 90
Memory 99
Swapping 23
Upper Memory Block 23
Y 135
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