The Atari Compendium/The Atari Compendium (Toad Computers) (1994).iso/files/umich/utils/whatis63.lzh/WHATIS63.DOC

Text File | 1992-07-29 | 25KB | 569 lines

                      WHATIS File Identifier v6.3
                  Copyright (c)1989-92 by Bill Aycock


WHATIS is a simple program that will identify over 125 different types of
files. It is mouse-driven and easy to use; everything is done from a single
dialog box.  Whatis runs in any resolution on any ST or TT, and uses under 17K
of your system's RAM.  This version will work as either a standalone program or
as a desk accessory (just rename the program file to .PRG or .ACC as you wish).

When run as a desk accessory, versions 5.2 and up of Whatis can act as a
"Whatis server" - specially-written programs can use Whatis to identify file
types for them!  (See the Whatis Server appendix for details.)  Starting with
version 5.3, you may also pass a filespec to Whatis on the command line to run
it as a TTP-like program.


Why use Whatis?  Let's say you're on your favorite BBS, and download a file
called SUPER.ARC.  You fire up your Arc Shell to extract the file, and it says
"I don't know how to handle this file!".  Whip out Whatis and take a look, and
you find out the file is really an LHarc archive - the uploader used the wrong
extender!  Just rename the file to SUPER.LZH and you're all set.

Another, darker scenario... a virus sneaks into your system and erases your
hard drive's directory.  Fortunately, you have a program that can recover your
files - unfortunately, it names all the files FILE0001, FILE0002, and so on!
Spend a little time with Whatis, and you may not figure out each file's
original name, but at least you'll know which are programs, which are .PI1s,
which are Calamus docs... a real help if you need it.



      Using Whatis
      ------------


Either run Whatis as a GEM program or choose Whatis from the Desk menu, and
the Whatis dialog box will appear.  Under the title bar you'll see three boxes
for a filename and file type, a file's header bytes, and the header byte
display mode. At the bottom of the dialog are three action buttons, marked
"Choose a file", "Next file", and "Exit".

To use Whatis, either click on "Choose a file" or just press C or Return or
the down arrow. You'll be presented with the GEM file selector; use the file
selector to choose your mystery file.  Whatis will read the first few bytes of
the file in question and check if these bytes match a known "signature" of a
specific type of file.  (Note: Whatis needs at least eight bytes to make a
reasonable guess of the file type; if your file is too small, you'll see an
error message and you'll get a chance to choose another file.)

Then you'll return to the Whatis box.  The small message box in the main
title bar displays the path you selected.  The first large box under the title
bar shows the name of the file you chose, its size (in small numbers on the
upper right), and the type of file it is.  If Whatis doesn't recognize the file
type, it will show up as "text or data".  The next box, labeled "header bytes",
displays the first few bytes of your file.  You can view this file header in
either hexadecimal or ASCII form;  click the "ASCII" or "HEX" button, as
desired, in the small box under the header byte display, or press the left or
right arrow keys.

If you used any wildcards when you selected your mystery file, the "Next
file" button at the bottom of the screen will be enabled (not grayed out), and
it will be the default button (signified by a thicker border).  To check the
next file that matches the filename pattern you chose, simply click this button
or press Return, or the space bar or down arrow.  (Note: files matching the
file mask are NOT displayed in alphabetical order; they appear in the same
order as they are on disk.)

From the main dialog you can identify another file, or return to whatever you
were doing by clicking the EXIT button or pressing UNDO or ESCape.  Simple!


You can reposition the Whatis dialog anywhere on screen.  Click on the title
area in the dialog, hold the mouse button down, and drag the outline wherever
you wish.  When you release the button, the Whatis dialog appears in the new
location.  If Whatis is running as a resident accessory, the new position is
saved between calls.


A complete list of the file types Whatis can recognize is included at the end
of this document.  Unfortunately, many file types do not contain a unique
signature in the first few bytes; Whatis can't identify such files unless a
certain file type is always a specific size (e.g., Degas .PI? pics).

Note that it _is_ possible to fool Whatis.  If a data file happens to start
with the same sequence of bytes as some other file type, it will be identified
incorrectly.  It is also difficult to distinguish between certain types of
files - for example, the signatures of low-rez TINY pics, resource files,
Neochrome pictures, and 8-bit Scrunch files look the same, so the ID box lists
all of those types.  Low-rez TINY pics produced with Vidi-ST sometimes look
identical to SAVEd BASIC (8-bit) files, so both types are listed in that box.



      Whatis and the Command Line
      ---------------------------


Whatis will accept a file spec on the command line in case you wish to run it
as a TTP-like program.  If you pass Whatis a command line, it will display a
list of the file name and type for all matching files. Your command line can
contain a full filespec, or just a path or filename (which may include
wildcards).  If you don't include a filename, all files in the path you specify
are checked; if you leave out the path, Whatis will check all the files in your
current directory that match the filename.

Leading and trailing blanks on the command line are ignored, and if you pass
more than one filespec only the last is used.  Normally Whatis will pause after
every 23 files and after all files have been displayed, and wait for you to
press a key before continuing.  If you press ESC or UNDO at this point, Whatis
will exit even if there are more files to identify.  (If you end the command
line with a plus sign ('+'), Whatis will _not_ perform these pauses.  See the
section below on setting a default pause mode for more information.)

Command line mode can be useful if you wish to run Whatis from a CLI (command
line interface), or from within a terminal program such as Flash.  To run
Whatis from within Flash, enter a command like this on the command line:

            Command> exec whatis e:\today\*.*

This command will make Whatis check every file in your E:\TODAY\ folder and
display a line showing the filename and file type.  From a real CLI, enter

            whatis e:\today\*.*

and Whatis will show you the same display, then wait for you to press a key.


NOTE: If the command line you pass is empty, or contains all blanks or just a
plus sign, Whatis will display its dialog box just as if you had run it as a
standard GEM program.  If you've run Whatis as a real TTP program, the mouse
may be turned off when the dialog appears.  If this happens, you may be able to
run Whatis using the keyboard equivalents instead of the mouse (UNDO to exit,
RETURN to select a file, etc.).  This is different from the behaviour of a real
TTP-only program, which is the reason for the term "TTP-like".



      Whatis and Data Diet
      --------------------


Data Diet is Double Click Software's excellent program for saving huge gobs
of space on your hard disk.  Although Whatis can recognize DD 'dietized' files,
there's a catch- you can't have DD active in your system to find one!!  The
reason is simple... Data Diet acts behind the scenes.  When a program (e.g.,
Whatis) reads a file, DD quickly and silently decodes the file to its original
form before the program gets the data.  That means there's no DD identifier to
find, so Whatis reports the actual file type.



      Setting a Default Path and Pause Mode
      -------------------------------------


When you run Whatis, the file selector normally comes up preset to the root
directory of the drive Whatis loaded from.  But if you normally download files
to a particular folder