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Mass Deletes (PC Magazine Vol 5 No 13 July 1986 User-to-User) It's easy to mass-erase unwanted files by using the ERASE command with ? and * wildcard characters. This works file if the multiple files have some common elements to their names or extensions, but to erase multiple files without common portions of the names you normally have to issue the ERASE command once for each file you want to get rid of. To get around this problem, and to make it easier to erase several files with one command, use this WIPEOUT.BAT file: ECHO OFF :LOOP IF !%1 == ! GOTO ALLDONE IF EXIST %1 GOTO OKFILE ECHO File %1 not found .... GOTO GOON :OKFILE ERASE %1 :GOON SHIFT GOTO LOOP :ALLDONE To use WIPEOUT.BAT, type the files you want to erase after the WIPEOUT, with spaces between them. For instance: WIPEOUT c.doc c.wks d.doc would remove c.doc, c.wks, and d.doc from your disk with a single command. The batch file checks to see whether the files you specified are on your disk, tells you if they're not, and erases them if they are. It uses SHIFT to juggle the specified filenames into the single %1 replaceable parameter, and an IF !%1 == ! test to see if it's finished. ----------------------------------------------------------------- ECHO OFF (PC World July 1986 & November 1986 Star-Dot-Star) The default setting of ECHO ON for batch file commands can be quite annoying. The obvious solution is to include an ECHO OFF command at the beginning of every batch file. This has the equally annoying effect of displaying the ECHO OFF command whenever the batch file executes. The ultimate solution is to patch COMMAND.COM to make ECHO OFF the default. For DOS 3.1, simply change the appropriate byte from 1 to 0. To do so, use a copy of COMMAND.COM and proceed as follows: A>debug command.com -e 1967 00 -w Writing xxxx bytes -q For DOS 2.1, patch COMMAND.COM as follows: A>debug command.com -e 096e 00 -e 1734 3c 1f -e 366e 0d 0a 24 -e 3672 26 c6 06 6e -e 3676 09 00 e9 05 e8 -w Writing 4580 bytes -q ----------------------------------------------------------------- Pause, S'il Vous Plait (PC Magazine August 1986 User-to-User) If you distribute disks with batch files on them to non-English speaking users, the message "Strike a key when ready ..." generated by the PAUSE command may be meaningless. To remedy this, substitute your own message by using ECHO and get rid of the normal English message by redirecting PAUSE to NUL. This feature works only in DOS 3.0 or later. A French version would look like this: ECHO OFF ECHO Presser une touche pour continuer PAUSE >NUL Redirecting messages to NUL is a useful technique that can also prevent general batch file screen clutter. Users have learned to start their systems by creating a RAMdisk and copying their most frequently used files to it. Even with ECHO OFF, the results is a string of "1 File(s) copied" messages. To keep the screen clean, add a ">NUL" to the end of each COPY instruction. ----------------------------------------------------------------- Putting DOS Variables to Work (PC World August 1986 Star-Dot-Star) Buried within the DOS manual is a discussion of a feature that enables you to create variables for use within batch files. This powerful feature makes creating sophisticated batch files a cinch. The technique works because DOS treats the percent sign (%) as a special mark that identifies replaceable parameters. When you place percent signs on both sides of a name, DOS looks to an area of memory called the environment to find the value that replaces the variable name. You can put values in the environment with the SET command. Suppose you need to use a command frequently within a batch file. You could use the SET command to store that command in the environment under a short name (such as Z), and then use the variable %Z% within the batch file in lieu of the command itself. SKIPLINE.BAT illustrates such a situation. Values remain in the environment until you remove them or restart the computer. Because of this, DOS variables can be enlisted to pass values between batch files. One batch file can set a value in the environment; subsequent batch files can test that value using the IF subcommand, or they can use the value directly as demonstrated in SKIPLINE.BAT. Editor's Note: DOS reserves 127 bytes for environment space and expands that amount automatically unless you've loaded memory-resident software such as GRAPHICS.COM or SideKick. If you run out of environment space (which will be indicated by a DOS error message), use the technique outlined in "For Environmentalists" in PC World April 1986 Star-Dot-Star. (This article is contained in the previous tips file, DOSTIPS4.ARC. -drw-) ----------------------------------------------------------------- Tax-Free Solution (PC World August 1986 Star-Dot-Star) According to IRS regulations, anyone who uses a computer for both personal and business purposes must keep contemporaneous records to document deductible expenses. You can buy any of several utility programs that monitor PC usage, but you can also accomplish the task with the batch file USELOG.BAT. USELOG.BAT relies heavily on DOS redirection capabilities. It requires that you first create a file called CR.DAT and keep it on disk so DATE and TIME commands can be redirected. To create CR.DAT, type: COPY CON:CR.DAT <Enter>, press <Enter> again, and then <Ctrl>-Z and <Enter>. Be careful when creating USELOG.BAT; the presence and placement of many characters are critical. This is especially true for the greater-than and less-than symbols; if you omit one where two are required, the contents of the master file may be erased each time USELOG.BAT is run. You can invoke the program in two ways: type USELOG followed by up to nine words that describe the purpose of the computer session. (Do not use the greater-than or less-than symbols in your description.) Or simply type USELOG and await prompting for a description. If you opt for the latter method, you must remember to press <Ctrl>-Z followed by <Enter> to mark the end of the description. When it is run, USELOG.BAT appends the date, time, and session information to the master file USELOG.DAT. The program performs with acceptable speed on a floppy-based system and executes in a flash when run on a hard disk. If you have a RAM disk, you may want to modify USELOG.BAT to operate on RAM-based files, then copy the master file onto a hard or floppy disk. Once the program is working, you can easily document all your computer activity -- including changing tasks after starting your PC. echo off cls rem Note: Requires file CR.DAT containing 1 blank line date<cr.dat>>uselog.dat time<cr.dat>>uselog.dat cls echo Purpose: >>uselog.dat if X==%1X goto cont echo Updating usage log... echo %1 %2 %3 %4 %5 %6 %7 %8 %9 >>uselog.dat goto end :cont echo Describe the purpose of this computer session, echo then press Ctrl-Z and then press ENTER: copy use log.dat+con uselog.dat/b >nul :end ----------------------------------------------------------------- Fast IBM Batch File Editor (COMPUTE! Magazine September 1986 by Tony Roberts) The power of the batch file quickly becomes evident to anyone who works regularly in DOS. The AUTOEXEC.BAT handles a variety of chores each time the system is booted, and any number of other BAT files stand by, ready to help with such tasks as initializing applications, sending out printer codes, and presenting program menus. The problem with batch files is that to be effective and helpful, they need to be adjusted as your system grows and your applications change. Performing the necessary batch-file maintenance, however, is often so cumbersome that it's discouraging. Loading a full-blown word processor or even using EDLIN to edit a five- to ten-line batch file can be a lot more time and trouble than it's worth. EDBAT.COM is a full-screen editor with very limited features. Because it is designed for speed, it limits itself to files of fewer than 512 bytes -- adequate for most batch files. When called, the program clears the screen and displays the file you want to edit. Using the cursor keys, you can move to the appropriate place, make the necessary changes, and press Alt-S to save the edited file. It is not impossible to open a file, edit it, close it, and be back at the DOS prompt in as little as 15 seconds. The price you pay for this fast operation is that EDBAT has very few features. You're essentially limited to the regular character keys and the cursor keys. The Insert key does not work, the Delete key does not work, nor do the function keys perform any function. The Backspace key moves the cursor back a character, but it does not perform a delete. For batch file editing, none of these is particularly restrictive. You're usually just performing one or two simple operations such as adding, deleting, or correcting a line. EDBAT can handle all these tasks efficiently. EDBAT.COM is created from the EDBAT.BAS listing below. To run EDBAT.COM, enter this line at the DOS prompt: EDBAT filename EDBAT.COM must be on the disk in the current drive when you enter this command. Filename is the name of the file you wish to edit. Full drive and subdirectory specifications are allowed when indicating a filename. If the file is too long or if EDBAT is unable to open the file, the program will print a message and exit. If the file you have specified does not exist, EDBAT assumes you are creating a new file. The file you are to edit is displayed on the screen below a line containing the program title and the name of the current file. If you have started a new file, the screen's work area will be blank. Use the cursor keys to move around the file, editing as needed. Notice that a triangle signals the end of each line. If you decide to cut a line short, move to the appropriate spot and press Enter. A trianble is inserted and the cursor moves to the beginning of the next line. The screen may continue to show characters beyond the end-of- line marker, but they will be ignored when the file is saved. To delete an entire line, simply move to the first position on that line and press Enter. An end-of-line marker appears at that spot, indicating that the line will be ignored. Inserting a line is slightly more difficult since there is no insert function. Move the cursor to the end-of-line marker on the line that will precede your new line. Press Ctrl-Y and a down-arrow character will replace the end-of-line marker. Add the new line right after the down arrow and press Enter as usual. When the file is saved, the lines will be adjusted. When you're finished editing, press Alt-S to save the file. The program's save routine reads the screen and saves what it sees to your file. It begins with the first line of the text area and continues until it finds a space in the first position of any line. EDBAT ignores any characters in a line which follow the first end-of-line marker. The only other option the program offers is Alt-Q, the Quit option, which returns you to DOS without changing the original file. In nearly every case, your entire file will fit easily on the screen. If part of your file scrolls off the screen, use Alt-Q to quit and find another method of editing the file. EDBAT cannot save what it cannot see. EDBAT does not make a backup copy of your original file. In most cases, though, a backup copy of a very short file is superfluous. EDBAT.COM Command Summary: Alt-Q Quit Alt-S Save Ctrl-Y Multistatement delimiter (prints as a down arrow) Enter End-of-line (prints as left-pointing triangle) Space Space in first position of line signals text end EDBAT.BAS: 10 CLS 20 OPEN "EDBAT.COM" AS 1 LEN=1 30 FIELD 1,1 AS A$ 40 PRINT:PRINT"Writing EDBAT.COM to disk....." 50 FOR I=1 TO 8:READ B$:GOSUB 130:NEXT I 60 FOR I=1 TO 75:B$="5F":GOSUB 130:NEXT I 70 B$="24":GOSUB 130 80 FOR I=1 TO 74:B$="0":GOSUB 130:NEXT I 90 FOR I=1 TO 648:READ B$:GOSUB 130:NEXT I 100 CLOSE 110 PRINT:PRINT"EDBAT.COM has been created." 120 END 130 'Write byte to disk 140 LSET A$=CHR$(VAL("&H"+B$)) 150 PUT #1 160 RETURN 170 DATA E9,E0,0,45,64,42,61,74,2,0 180 DATA 2,50,6C,65,61,73,65,20,73,70,65,63,69,66,79,20 190 DATA 66,69,6C,65,6E,61,6D,65,2E,D,A,24,45,72,72,6F 200 DATA 72,20,6F,70,65,6E,69,6E,67,20,66,69,6C,65,2E,D 210 DATA A,24,46,69,6C,65,20,74,6F,6F,20,6C,6F,6E,67,2E 220 DATA D,A,24,FC,BF,54,1,BE,80,0,AC,A2,99,1,FE,E 230 DATA 99,1,3C,0,75,9,BA,A1,1,E8,7,2,E8,25,2,AC 240 DATA 3C,D,74,3,AA,EB,F8,E8,BA,1,73,E,3D,2,0,74 250 DATA 30,BA,BC,1,E8,EC,1,E8,A,2,BA,26,4,8B,1E,9A 260 DATA 1,8B,E,9F,1,B4,3F,CD,21,3B,6,9F,1,75,C,E8 270 DATA A0,1,BA,D2,1,E8,CB,1,E8,E9,1,A3,96,1,E8,91 280 DATA 1,E8,CB,1,BA,3,1,E8,B9,1,C6,6,9E,1,0,C6 290 DATA 6,9D,1,14,E8,60,1,BE,55,1,33,C9,8A,E,99,1 300 DATA AC,8A,D0,80,FA,61,72,3,80,E2,DF,E8,9C,1,E2,F0 310 DATA C6,6,9E,1,2,C6,6,9D,1,0,E8,3A,1,83,3E,96 320 DATA 1,0,74,1F,FC,BE,26,4,8B,E,96,1,AC,8A,D0,80 330 DATA FA,D,75,7,B2,11,E8,71,1,B2,D,E8,6C,1,E2,EC 340 DATA E8,14,1,B4,0,CD,16,3C,0,74,13,3C,D,74,A,3C 350 DATA 8,B4,4B,74,1C,3C,19,72,EA,E8,1F,1,EB,E5,80,FC 360 DATA 48,75,E,80,3E,9E,1,2,74,D9,FE,E,9E,1,E8,E6 370 DATA 0,80,FC,4B,75,E,80,3E,9D,1,0,74,C6,FE,E,9D 380 DATA 1,E8,D3,0,80,FC,4D,75,E,80,3E,9D,1,4F,74,B3 390 DATA FE,6,9D,1,E8,C0,0,80,FC,50,75,E,80,3E,9E,1 400 DATA 18,74,A0,FE,6,9E,1,E8,AD,0,80,FC,10,75,6,E8 410 DATA FD,0,E8,F,1,80,FC,1F,75,89,C7,6,96,1,0,0 420 DATA BF,26,4,C6,6,9E,1,2,C6,6,9D,1,0,E8,87,0 430 DATA C6,6,95,1,0,B4,8,CD,10,3C,20,74,4E,3C,11,75 440 DATA 9,FE,6,9E,1,E8,6F,0,EB,DE,80,3E,95,1,50,77 450 DATA 18,B4,8,CD,10,3C,11,74,10,3C,19,75,1C,B0,D,AA 460 DATA FF,6,96,1,B0,A,EB,11,90,B0,D,B4,A,AB,83,6 470 DATA 96,1,2,FE,6,9E,1,EB,AF,AA,FF,6,96,1,FE,6 480 DATA 95,1,FE,6,9D,1,E8,2E,0,EB,BF,F8,BA,55,1,B4 490 DATA 3C,B9,0,0,CD,21,73,9,BA,BC,1,E8,65,0,E8,83 500 DATA 0,8B,D8,8B,E,96,1,BA,26,4,B4,40,CD,21,E8,21 510 DATA 0,E8,5B,0,E8,6D,0,8A,36,9E,1,8A,16,9D,1,B4 520 DATA 2,CD,10,C3,F8,BA,55,1,B0,2,B4,3D,CD,21,A3,9A 530 DATA 1,C3,8B,1E,9A,1,B4,3E,CD,21,C3,8A,D0,80,FA,D 540 DATA 74,8,E8,25,0,FE,6,9D,1,C3,B2,11,E8,1B,0,B2 550 DATA D,E8,16,0,B2,A,E8,11,0,FE,6,9E,1,C6,6,9D 560 DATA 1,0,C3,50,B4,9,CD,21,58,C3,B4,2,CD,21,C3,B4 570 DATA F,CD,10,88,3E,9C,1,B4,0,B0,2,CD,10,B4,5,B0 580 DATA 0,CD,10,C3,CD,20 ----------------------------------------------------------------- Best Batch Branch (PC Magazine Vol 5 No 8 Apr 29, 1986 User-to-User) Long batch files containing numerous "if ... goto" conditional statements tend to slow down dramatically as processing moves further along. DOS searches slowly for each new label from the top of the file, yielding a pathetic 5- to 10-second delay, even on an AT, if the label occurs near the end of a long batch. There is a way to get rid of all the labels and "if errorlevel ... goto" statements, allowing a batch file to work at top speed and still contain numerous conditional branches. Most batches can be controlled with a simple Y(es) or other single-key response to each request. The GETKEY technique described in an earlier User-to-User sets a different errorlevel for every response. Because DOS returns a "true" if errorlevel <= the set value, batch files ordinarily require four "if errorlevel" tests to obtain "true" on Y or y but "false" on other keys. GETYES.COM performs these tests, thereby removing them from the batch. It sets errorlevel 255 for Y or y and errorlevel 0 for any other key. This lets you directly perform an operation with the statement "if errorlevel 255 (perform some DOS function)". GETYES.COM is created with GETYES.BAS below. You can next "if" conditionals on one line of a batch file for further flexibility and control; for example, "if errorlevel 255 if exist filename (perform some DOS function)" or "if errorlevel 255 if x == %1 (perform some DOS function)". This doesn't seem to be documented in the DOS manual. 100 'GETYES.BAS 110 OPEN "GETYES.COM" AS #1 LEN=1 120 FIELD #1,1 AS D$ 130 FOR B=1 TO 18 140 READ A$:LSET D$=CHR$(VAL("&H"+A$)) 150 PUT #1:NEXT:CLOSE 160 DATA B4,00,CD,16,3C,59,74,04,3C 170 DATA 79,75,02,B0,FF,B4,4C,CD,21 Editor's Note: This technique makes batch branching a pleasure. If you want to use N and n rather than Y and y to trigger errorlevel, substitute 4E for 59 in line 160 and 6E for 79 in line 170, and change the reference from GETYES.COM to GETNO.COM. To test this after creating the GETYES.COM program, use this TESTTHIS.BAT file: echo off :start echo Hit y or Y or another key getyes if errorlevel 255 goto :yes goto :no :yet echo ...you said yes goto :continue :no echo ...you didn't hit y or Y :continue echo Now, want to quit (y/n)? getyes if errorlevel 255 goto :exit goto :start :exit The nesting abilities allow even more power. To test these, revise the fifth line of TESTTHIS.BAT to read: if errorlevel 255 if Z==%1 goto :yes Then, if you execute TESTTHIS.BAT again, hitting Y or y at the first prompt will not result in a branch as it did earlier. To make both of the nested conditions true, instead of executing the batch file by typing TESTTHIS, at the DOS prompt type: TESTTHIS Z and hit Y or y when asked. The Z after the filename will replace the %1 parameter, and since both conditions (the errorlevel and the Z==Z) are true, the batch file will work as advertised. If you try this, be sure to type in a capital Z; DOS, which much of the time converts lowercase keyboard inputs into uppercase ones, is case-sensitive here. Case Closed (PC Magazine Vol 5 No 16 Sept 30, 1986 User-to-User) The GETYES.COM batch branch technique relies on Y or N responses and works only if the number of choices is small. A better method for branching is to adapt the GETKEY.COM program on which GETYES is based. GETKEY reports different IF ERRORLEVEL values for upper- and lowercase letters. It's smarter to add a line in GETKEY that will convert all lowercase letters to uppercase. To do this, use an ASCII word processor or DOS's COPY.COM to create a script called GETFIX, containing the lines: N GETNEW.COM A MOV AH,0 INT 16 AND AL,DF MOV AH,4C INT 21 RCX A W Q Then create the GETNEW.COM file by putting GETFIX on the same disk as DEBUG and typing: DEBUG < GETFIX GETNEW.COM will let you work with just capital-letter values, reducing the IF ERRORLEVEL tests by half. The example batch file below will let you type in either A, B, or C (or a, b, or c) and will then figure out with a minimum of tests which keys you hit. ECHO OFF :MENU ECHO ------------------------------ ECHO Hit A, B, or C (or a, b, or c) ECHO -- or hit Q (or q) to quit -- ECHO ------------------------------ GETNEW IF ERRORLEVEL 82 GOTO OOPS IF ERRORLEVEL 81 GOTO END IF ERRORLEVEL 68 GOTO OOPS IF ERRORLEVEL 67 GOTO C IF ERRORLEVEL 66 GOTO B IF ERRORLEVEL 65 GOTO A GOTO OOPS :C ECHO YOU HIT A C GOTO MENU :B ECHO YOU HIT A B GOTO MENU :A ECHO YOU HIT AN A GOTO MENU :OOPS ECHO WRONG ... GOTO MENU :END While reducing the number of IF ERRORLEVEL tests will speed up batch file execution, you can make your batch files run much faster by running them out of RAMdisks and arranging the test properly. Since batch files search for labels from the top of each batch file, put nonessential statements at the bottom (and GOTO them), and put the labels that users are most likely to choose nearest the top. Finally, don't exit with an :END label at the end of the batch file, which is the most time-consuming search of all. Instead, execute a dummy batch file. Since DOS doesn't allow nesting of batch files, this will drop you to the DOS prompt. Editor's Note: ANDing any ASCII value with 223 (hex DF) will capitalize lowercase letters and leave uppercase letters alone. The logical AND operation works by comparing two values (the example below compares 1 bit at a time) and returning a 1 only when both values are nonzero. 1 AND 1 = 1 1 AND 0 = 0 0 AND 1 = 0 0 AND 0 = 0 223 equals binary 11011111. Capital A (decimal 65) is binary 01000001, while lowercase a (decimal 97) is binary 01100001. The AND operation on these numbers could be represented as: 01000001 (65) AND 11011111 (223) -------- 01000001 (65) 01100001 (97) AND 11011111 (223) -------- 01000001 (65) ANDing either a 0 or a 1 with 1 in effect leaves the value alone, and ANDing both a 0 and 1 with 0 in effect turns the value into a 0. The binary number 11011111 forces the 2^5 bit -- the sixth one from the right -- to become a 0 and leaves all the other bits the way they were. (The rightmost bit is 2^0; the left most is 2^7.) The only difference between a lowercase letter and its capital counterpart is that the 2^5 bit is "set" (=1) in the lowercase version. ANDing it with 11011111 "unsets" the bit, chaning it to a 0 and lowering the ASCII value by 32. To reverse the process and turn capital letters into lowercase ones, use the logical OR operation to OR a value with 32. 1 OR 1 = 1 1 OR 0 = 1 0 OR 1 = 1 0 OR 0 = 0 32 equals binary 00100000. Since ORing either a 1 or a 0 with 0 in effect leaves the value alone, and ORing either a 1 or a 0 with 1 in effect turns the value into a 1, the binary number 00100000 forces the 2^5 bit to become a 1 and leaves all the other bits the way they were. This "sets" the unset 2^5 bit in an uppercase letter, changing it to a 1 and raising the ASCII value by 32. 01000001 (65) OR 00100000 (32) -------- 01100001 (97) 01100001 (97) OR 00100000 (32) -------- 01100001 (97) GETNEW.COM is a significant improvement over the previous GETKEY.COM routine. Using GETNEW in your batch files will let you offer 26 choices -- amost certainly enough -- while keeping the number of IF ERRORLEVEL tests to a minimum. Of the other batch file enhancement techniques suggested, by far teh most important is to run any branching batch file from a RAMdisk. the VDISK.SYS "virtual disk" comes free with DOS and is smart, flexible, and extremely easy to use. You don't even have to change any system board DIP switch settings to take advantage of a RAMdisk's speed gain. One more note -- DOS in fact does allow batch file nesting. To do so, preface the name of the batch file to be nested with COMMAND /C, which runs it out of a secondary command processor. (See "Nested FORs" PC Mag Vol 5 No 16 Sept 30, 1986 User-to-User below.) Batch Feedback (PC Magazine Vol 5 No 21 Dec 9, 1986 User-to-User) The GETNEW.COM program provides a useful way to implement an interactive batch file in which a letter typed on the keyboard sets the ERRORLEVEL to its corresponding ASCII value. However, the program does not echo the character typed. Since batch files execute slowly, even on a hard disk system, an impatient user may repeatedly press the key until a response is seen. These extra keystrokes are stored in the input buffer and may cause undesired effects once control is passed to a program. A simple modification of GETNEW that provides feedback to the user by echoing the character typed is: N GETNEW.COM A MOV AH,0 INT 16 OR AL,20 MOV DL,AL MOV AH,02 INT 21 MOV AH,4C INT 21 RCX 10 W Q (Name this file GETNEW.SCR. Then use DEBUG to create GETNEW.COM by typing: DEBUG < GETNEW.SCR.) Since most users leave CapsLock off and work with lowercase letters, the program is modified to convert all input to lowercase. If uppercase conversion is preferred, replace the OR AL,20 with AND AL,DF The batch file below is a program that uses GETNEW to run any of a selection of programs listed on a menu. To speed execution, the menu is stored in an ASCII file MENU.TXT (see below) in the root directory. This batch file can replace a number of smaller files used to call individual programs. Since each batch file replaced uses 4,096 characters of storage on a hard disk regardless of how small it is, the savings in disk storage space can be considerable. echo off :restart cls prompt cd\ path\ type MENU.TXT getnew echo ...Wait... if errorlevel=114 goto errmsg if errorlevel=113 goto q if errorlevel=105 goto errmsg if errorlevel=104 goto h if errorlevel=103 goto g . . . if errorlevel=97 goto a :errmsg echo Invalid response. goto restart :a echo Running [program a]... cd\[subdirectory a] [batch instructions to run program a] . . . goto restart :b echo Running [program b]... cd\[subdirectory b] [batch instructions to run program b] . . . goto restart :c [etc.] . . . :q cls prompt type HELP for menu$_$n$g Following is the ASCII file MENU.TXT which should be stored in the root directory. The file ends after the : on the last line without a carriage return, so that the input letter to be echoed will appear on the same line as the request. type to do this ------- ---------------- a run [program a] b run [program b] c run [program c] . . . h run [program h] q exit this menu to DOS When in DOS, type HELP to get back to this menu Type letter (a through h or q): Editor's Note: This modification can come in handy if you run your batch files off floppies or slow hard disks. But it's far more efficient to create a small RAMdrive when you boot up (the DOS VDISK.SYS will handle the job), copy your important batch files to the RAMdrive, PATH to it, and execute everything out of memory. The technique of using the TYPE MENU.TXT command rather than a string of ECHO statements to display a long menu is a good one, as is leaving the final carriage return off the last line of the .TXT file that acts as a prompt. (Don't omit carriage returns from final ECHO commands, however, or DOS won't execute them properly.) The 4K minimum file length applies just to XT hard disks under DOS 2.x; an AT running DOS 3.x gets away with files half that size. ----------------------------------------------------------------- Nested FORs (PC Magazine Vol 5 No 16 Sept 30, 1986 User-to-User) Trying to next FOR batch subcommands usually results in a "FOR cannot be nested" error message. The solution is to load a COMMAND /C secondary command processor before the second FOR. This technique will work more than the two levels deep in the example shown below. If you try this technique in direct DOS mode (rather than in a batch file), use single % signs rather than the double % signs required for batch files. for %%a in (1 2 3) do for %%b in (A B C) do echo %%a %%b for %%a in (1 2 3) do command/c for %%b in (A B C) do echo %%a %%b Editor's Note: DOS doesn't seem especially picky about what COMMAND /C syntax you use. All of these variables work fine when inserted in the example shown above: COMMAND /C FOR COMMAND/C FOR COMMAND /CFOR COMMAND/CFOR ----------------------------------------------------------------- Resounding ECHOs (PC Magazine Vol 5 No 16 Sept 30, 1986 PC Tutor) Several readers pointed out that using ASCII 255 to get DOS 3.1 to ECHO blank lines (PC Tutor Vol 5 No 10 May 27, 1986), an alternative solution (a patch to COMMAND.COM) had already appeared in User-to-User Vol 4 No 24 November 26, 1985. The COMMAND.COM patch is not a good solution in this case. The patch doesn't really solve the problem, since for every new DOS version somebody will have to figure out where to put similar new patches. ECHO has been fixed in DOS 3.1, so patching COMMAND.COM to duplicate the effect of an old bug doesn't make sense. ECHO should not act differently if it is followed by one blank space or by two blank spaces, as it does in DOS 2.0 through 3.0. The real problem with ECHO is its insistence on issuing "Echo is on" and "Echo is off" messages. If ECHO did not dish out these useless messages, it would simply echo a blank line when entered without a parameter. In the case at hand, the person who asked about echoing blank lines was involved in maintaining batch files in a corporate setting where they are used on many different PCs. Patching COMMAND.COM on each of these machines rather than changing the batch files (which require periodic redistribution anyway) didn't seem to be a reasonable approach. The use of EDLIN, with its redirection of standard input, illustrated some valuable techniques that could be applied in other circumstances where changes must be made in several different files. The recommendation to change the ECHO statements to echo an ASCII 255 (which displays as a blank) is not the only good fix, however. Several readers pointed out that: ECHO. will print a blank lines, as will also ECHO: Both are cleaner and much easier to create with most text editors. Note that the period and colon must immediately follow ECHO. You can also use a slash, backslash, double quote, left or right bracket, or a plus sign immediately following the word ECHO. What all these characters have in common is that they may not be used in file or command names (thus they obviously aren't part of the command), they are not delimiters, and they serve no other purpose on a command line (as would the angle brackets, for instance). All were tested with DOS 3.2 and they work. Another reader suggested creating ASCII files containing the text to be displayed and using the batch file to TYPE these files to the screen after turning ECHO off. This is most useful when creating full-screen displays from batch files, since you can put ANSI control sequences in the file for moving the cursor around and highlighting. ----------------------------------------------------------------- Batch String Comparer (PC Magazine Vol 5 No 17 Oct 14, 1986 User-to-User) DOS makes it easy to control branching by passing parameters into batch files form the command line. You can then use IF statements to compare such parameters and branch accordingly. But DOS is case sensitive, which means that a string N characters long requires 2^N IF statements to compare all of the permutations of uppercase and lowercase letters. A string containing the three characters ABC would require eight IF statements (testing for aBc, ABc, aBC, and so on) to exhaust every possible combination. This increases execution time dramatically. COMPARE.COM compares two strings and ignores the case of the alphabetic characters. On return, it sets ERRORLEVEL 255 if both strings are equal and ERRORLEVEL 0 if they are not equal or if a syntax error has occurred. After executing COMPARE.COM, your batch file may take appropriate action with the statement "IF ERRORLEVEL 255 (do something)." To test COMPARE.COM, run the sample COMPTEST.BAT batch file. At the DOS prompt type: COMPTEST hello HELLO and it will respond with the message: The strings are equal. IF ERRORLEVEL is a necessity in large batch files, and this lets you use words rather than single characters to trigger branching, making things far friendlier. COMPTEST.BAT: echo off if %2!==! goto oops compare %1==%2 if errorlevel 255 goto match echo The strings are not equal. goto end :match echo The strings are equal. goto end :oops echo The format required is: echo COMPTEST STRING1 STRING2 :end COMPARE.BAS: 100 'COMPARE.BAS: Creates COMPARE.COM. 110 PRINT "Checking DATA statements ...." 120 FOR B=1 TO 9:FOR C=1 TO 17:READ A$:IF C<17 THEN 140 130 Z#=Z#+VAL(A$) 140 NEXT:NEXT 150 IF Z#=13419 THEN RESTORE:GOTO 180 160 PRINT "Wrong number of DATA statements, or error in a big" 170 PRINT "number at the end of a line -- check and redo.":END 180 FOR B=1 TO 9:FOR C=1 TO 16:READ A$:TTL=TTL+VAL("&H"+A$) 190 NEXT 200 READ S:IF S=TTL THEN 220 210 PRINT "DATA error in line";B*10+260;" -- check and redo.":END 220 TTL=0:NEXT:RESTORE 230 OPEN "COMPARE.COM" AS #1 LEN=1:FIELD #1,1 AS D$ 240 FOR B=1 TO 9:FOR C=1 TO 16:READ A$:LSET D$=CHR$(VAL("&H"+A$)) 250 PUT #1:NEXT:READ DUMMY$:NEXT:CLOSE 260 PRINT "COMPARE.COM created." 270 DATA BE,81,00,FC,AC,3C,20,74,FB,3C,0D,74,4C,4E,56,5F,1726 280 DATA 2B,C9,AC,3C,3D,74,17,3C,20,74,0A,3C,0D,74,3A,E8,1373 290 DATA 44,00,41,EB,ED,AC,3C,20,74,FB,3C,3D,75,2B,AC,3C,1749 300 DATA 3D,75,26,AC,3C,20,74,FB,4E,56,2B,DB,AC,3C,0D,74,1634 310 DATA 0A,3C,20,74,06,E8,1E,00,43,EB,F1,3B,CB,75,11,5E,1519 320 DATA B0,FF,F3,A6,74,0C,EB,08,90,B4,09,BA,74,01,CD,21,2085 330 DATA B0,00,B4,4C,CD,21,3C,61,72,09,3C,7A,77,05,24,5F,1387 340 DATA 88,44,FF,C3,53,79,6E,74,61,78,20,65,72,72,6F,72,1887 350 DATA 0D,0A,24,00,00,00,00,00,00,00,00,00,00,00,00,00,59 COMPARE.ASM: compare segment ; ;program to compare two strings ;case of letters will be ignored in the comparison ;for use in batch files for comparing strings ; ;syntax: compare string1 string2 ; ;errorlevel 255 = same string ;errorlevel 0 = not same string or syntax error ; main proc far assume cs:compare,ds:compare,es:compare,ss:compare org 100h doscall equ 21h prnt_msg equ 09h exit equ 4ch start: mov si,81h cld start_first_string: lodsb cmp al,' ' je start_first_string cmp al,0dh je error dec si push si pop di sub cx,cx get_first_string: lodsb cmp al,'=' je equal_sign cmp al,' ' je white_space cmp al,0dh je error call uppercase inc cx jmp get_first_string white_space: lodsb cmp al,' ' je white_space cmp al,'=' jne error equal_sign: lodsb cmp al,'=' jne error start_second_string: lodsb cmp al,' ' je start_second_string dec si push si sub bx,bx get_second_string: lodsb cmp al,0dh je end_second_string cmp al,' ' je end_second_string call uppercase inc bx jmp get_second_string end_second_string: cmp cx,bx jne no_match pop si mov al,255 repe cmpsb jz end jmp no_match error: mov ah,prnt_msg mov dx,offset synt_msg int doscall no_match: mov al,0 end: mov ah,exit int doscall main endp uppercase proc near cmp al,'a' jb is_upper cmp al,'z' ja is_upper and al,5fh mov [si-1],al is_upper: ret uppercase endp synt_msg db 'Syntax error',0dh,0ah,'$' compare ends end start ----------------------------------------------------------------- Batch File Parameters (PC Magazine Vol 5 No 19 Nov 11, 1986 PC Tutor) If you try to prevent the omission of an important batch file parameter by using an IF command within a batch file, such as in the line: IF %1==GOTO ERROR you get a "Syntax Error" from DOS. There is a way to check for teh case of a null batch file variable. Just put some other character on both sides of the double equal sign, such as a slash: IF /%1==/ GOTO ERROR One of the best ways to learn about batch file tricks is by exploring the installation programs that software manufacturers often ship with their products. ----------------------------------------------------------------- Pruning the XTREE (PC Magazine Vol 5 No 20 Nov 25, 1986 Power User) XTREE is the hard disk organizer of choice, but its chief shortcoming is the mandatory read of the entire directory structure. This problem can be overcome by using the DOS 3.1 SUBST command, however. SUBST lets you substitute a drive letter for a path specification, and the drive letter is acceptable to XTREE. Invoke XTREE from a batch file called XTRE.BAT: ECHO OFF IF P%1==P GOTO FULL SUBST D: /D > NUL SUBST D:=%1 XTREE D: GOTO END :FULL XTREE :END The first SUBST turns off any previous SUBSTitutes. The second assigns the drive letter D to a pathname specified when invoking the batch file. For example, to examine the subdirectory \DOS\UTIL, enter: XTRE \DOS\UTIL Or, to work with the current default directory: XTRE In either case, once in XTREE, you can change back to a full directory display by logging on to the actual drive. Notice that the file begins checking to see if you included a pathname. If not, it jumps to FULL, and XTREE wakes up reading the entire directory structure. Editor's Note: This is one of the more inventive applications for SUBST. Be forewarned, however, that although you may use any drive letter (A through Z) as the substitute "drive," DOS normally assumes that the last drive is E:. If A: through E: are already taken up by real drives plus a RAMdisk, you'll have to add a new line to your CONFIG.SYS file. The line reads: LASTDRIVE = x where x is any letter, A through Z. The value of x becomes the highest driver letter that DOS will recognize. ----------------------------------------------------------------- Menu Making Made Easy (PC Magazine Vol 5 No 20 Nov 25, 1986 User-to-User) Using the ECHO command to provide prompts or a menu in a batch file is handy if the text is short. But try to display several lines or a long menu, and ECHO can be frustratingly slow. This is even more irritating in batch files that routinely loop back and redisplay such menus. The solution is to write a short .COM file that uses function 9 of interrupt 21. The only read drawback is that this technique won't let you display a $, since DOS uses this hex character 24 to mark the end of the output string. To create a MENU.COM file, get into DEBUG and type in the script shown below, substituting your own text for the dummy "Menu Selection 1" and "Menu Selection 2". To have MENU.COM display more than just two lines, precede each line with "DB'" and follow each with the line: DB 0D 0A However, make sure the very last line of text (and only that line) contains an extra hex 24, which is the $ that tells DOS your text is done: DB 0D 0A 24 When you've finished entering text and have typed the 24, hit the Enter key twice. They you tell DEBUG how long the file is by typing RCX and entering the length of the file in hex. You can figure out the length by subtracting hex 100 from the hex number directly above the RCX. In the example below, this number is 12E, so 12E - 100 = 2E. Once you're done, get into DOS and type MENU to display the text you've entered. A>DEBUG -N MENU.COM -A 100 XXXX:0100 MOV DX,0109 XXXX:0103 MOV AH,09 XXXX:0105 INT 21 XXXX:0107 INT 20 XXXX:0109 db 'Menu Selection 1 XXXX:0119 db 0D 0A XXXX:011B db 'Menu Selection 2 XXXX:012B db 0D 0A 24 XXXX:012E RCX CX 0000 :2E -W Writing 002E bytes -Q Editor's Note: MENUMAKR.BAS automates the process. It isn't fancy, but it will center lines if you want, and it handles all the file creation details for you. Since it always names the output file MENU.COM, if you use MENUMAKR more than once, be sure to remove any existing MENU.COM programs you may have created previously. 100 'MENUMAKR.BAS 110 CLS:DEF FNST$(Z)=MID$(STR$(Z),2) 120 DIM A$(24):A=1:TOTAL=0 130 PRINT "Enter your line of text #";FNST$(A);":" 140 LINE INPUT A$(A) 150 IF LEN(A$(A))>79 THEN A$(A)=LEFT$(A$(A),80):GOTO 220 160 PRINT "Want it centered (Y/N)?" 170 I$=INKEY$:IF I$="" THEN 170 180 IF INSTR("YyNn",I$)=0 THEN BEEP:GOTO 170 190 IF INSTR("YyNn",I$)>2 THEN 220 200 A$(A)=STRING$(40-INT(LEN(A$(A))/2),32)+A$(A) 210 PRINT STRING$(2,30);A$(A);CHR$(31) 220 A$(A)=A$(A)+CHR$(13)+CHR$(10) 230 IF A=24 THEN 290 ELSE A=A+1 240 PRINT CHR$(30);"Add any more text (Y/N)?" 250 I$=INKEY$:IF I$="" THEN 250 260 IF INSTR("YyNn",I$)=0 THEN BEEP:GOTO 250 270 IF INSTR("YyNn",I$)>2 THEN 290 280 PRINT CHR$(30);:GOTO 130 290 OPEN "MENU.COM" FOR OUTPUT AS #1 300 FOR B=1 TO 9:READ C:PRINT #1,CHR$(C);:NEXT 310 FOR B=1 TO A-1:PRINT #1,A$(B);:NEXT 320 PRINT #1,CHR$(36):CLOSE:END 330 DATA 186,9,1,180,9,205,33,205,32 ----------------------------------------------------------------- Capital Idea (PC Magazine Vol 5 No 20 Nov 25, 1986 User-to-User) DOS's IF batch-processing subcommand is case sensitive. This means that for each string comparison, you need two tests -- one for uppercase and one for lowercase -- such as: IF %1==TEST ECHO This is a match. IF %1==test ECHO This is a match. Even this redundant test does not guarantee a match if the string you enter is a mixture of uppercase and lowercase letters (as in Test or TeSt or TEst). This can easily happen if the string you enter is a city or a person's name or an oddly capitalized computer company -- or if you lean too long on the Shift key. DOS 2.1 and DOS 3.1 store user-entered replaceable parameters in two entirely different places: DOS 2.1 stores them in the critical error-handling segment, and DOS 3.1 stores them just below the environment. Because of this, two different programs -- CAPS2.COM and CAPS3.COM -- are required to remove the case sensitivity. Use the CAPSx.SCR file that applies to the version of DOS you are using and at the DOS prompt enter either: DEBUG < CAPS2.SCR or DEBUG < CAPS3.SCR Then insert CAPSx.COM at the beginning -- or just after ECHO OFF and CLS -- of your batch files and delete the duplicate IF string1== string2 commands. For example, a DOS 3.1 batch file called TEST.BAT that tested to see whether a user entered "MicroPro" would look like this: ECHO OFF IF %1!==! GOTO OOPS ECHO You entered %1 CAPS3 ECHO CAPS3.COM turned it into %1 IF %1==MicroPro ECHO It works GOTO END :OOPS ECHO Enter TEST MicroPro :END CAPS2.SCR: A MOV AX,[14] ADD AX,B2 MOV DS,AX MOV SI,A CMP BYTE PTR [SI],0 JZ 120 CMP BYTE PTR [SI],61 JB 11D CMP BYTE PTR [SI],7A JA 11D AND BYTE PTR [SI],5F INC SI JMP 10B INT 20 RCX 22 N CAPS2.COM W Q CAPS3.SCR: A MOV AX,[2C] SUB AX,C MOV DS,AX MOV BX,A ADD BX,10 MOV SI,BX CMP BYTE PTR [SI],3A JNZ 10B INC SI CMP BYTE PTR [SI],5C JNZ 10B CLD LODSB CMP AL,0 JNZ 11C CMP BYTE PTR [SI],0 JZ 136 CMP BYTE PTR [SI],61 JB 133 CMP BYTE PTR [SI],7A JA 133 AND BYTE PTR [SI],5F INC SI JMP 121 INT 20 RCX 38 N CAPS3.COM W Q ----------------------------------------------------------------- Blank Lines with ECHO (PC World November 1986 Star-Dot-Star) The ECHO command behaves differently with DOS 3.1 than it does with DOS 2.1. Under DOS 2.1, an ECHO command followed by several space characters would put a blank line on the screen. DOS 3.1, however, ignores spaces and responds by displaying the current ECHO status. A simple way to get the better of DOS and echo a blank line is to use the ECHO command followed by a space and ASCII character 255. To create this character, hold down the Alt key and press the digits 255 on the numeric keypad, then release the Alt key. Although you cannot see the difference between ASCII 255 and a space, DOS will not consider the line blank and will display a blank line as intended. Some word processors cannot accept the Alt-255 character. Thus, you may have to use the DOS EDLIN program to put the character into your batch files. ----------------------------------------------------------------- Spacing Out a Batch File (PC World November 1986 The Help Screen) A user inadvertently inserted a space in a batch file -- he accidentally placed a space between the second period and the first percent sign in the line: IF NOT .==.%1 GOTO %1 rendering the line ineffective. His solution was to place the first occurrent of the replaceable DOS parameter %1 to the left of the first period and the double equal signs. The line worked, even with spaces between the %1 and the period. Another line in the batch file, IF %1.==. GOTO HELP, also had a replaceable DOS parameter to the left of the double equal signs. Although this line will function correctly, it raises an interesting point about the placement of DOS's replaceable parameters. The location of the replaceable parameter is all-important, and a batch file's conditional test for a blank DOS parameter should use: if x==%1x command rather than: if %1x==x command because if the string to the right of the == matches the first character of the left string but the left string is longer, DOS will execute command incorrectly. You can demonstrate the bug by creating two different batch files, A.BAT and B.BAT, and then typing the line: IF NOT CONCEPT==CONC A B and pressing Enter. Because CONCEPT is not equivalent to CONC, DOS should perform A. Instead, it selects B. Although DOS 3.0 and later versions don't exhibit this bug, play it safe and always use the proper syntax. And watch those spaces. ----------------------------------------------------------------- Subdirectory Navigators (PC Magazine Vol 5 No 21 Dec 9, 1986 User-to-User) VAX mainframes offer several predefined symbols that greatly simplify movement through a hierarchical directory structure: UP, DOWN, OVER, and HOME. These pseudo-commands aren't significantly faster than VAX/VMS's SET DEFAULT command, but they are much more logically oriented. Four batch files called UP.BAT, DOWN.BAT, OVER.BAT, and HOME.BAT can be stored on a RAMdisk and used as if they were actual DOS commands. To go to the parent directory (the one up above the present directory), just type UP and hit Enter. To go to a subdirectory called DOS (located down below the present directory), just type DOWN DOS. Use OVER to move from the present directory to one having the same parent (move over to a directory on the same level). HOME will return you to the root directory. This is UP.BAT: ECHO OFF CD.. CD (The CD command lacking an argument simply displays the current directory.) This is DOWN.BAT: ECHO OFF IF "%1" == "" GOTO NODRSPEC CD %1 CD GOTO END :NODRSPEC ECHO Move down to where? :END This is OVER.BAT: ECHO OFF IF "%1" == "" GOTO NODRSPEC CD..\%1 CD GOTO END :NODRSPEC ECHO Move over to where? :END And this is HOME.BAT: ECHO OFF CD\ CD When using DOWN.BAT or OVER.BAT, be sure to enter the name of the subdirectory where you want to end up. If you don't specify one, the batch file will ask you where you want to go. (VAX symbol commands at work are not nearly so polie; they respond with a ver sarcastic "Really, to where?" prompt.) If you are using a RAMdisk, you should copy these files to it. If you are not using a RAMdisk, be sure to place the batch files on a directory specified by the PATH command in your AUTOEXEC.BAT file. ----------------------------------------------------------------- Printer Controls From Batch Files (PC Magazine Vol 5 No 22 Dec 23, 1986 Power User) A word processor can put an IBM Proprinter into near-letter-quality mode and leave it there when you exit to DOS. This can be annoying if you then wish to print out some files in draft quality mode. To reset the printer to draft mode, you could add the following line to your word processor batch file (immediately after the line calling up the word processor): TYPE DRAFT.ASC > LPT1: The file DRAFT.ASC contains the following line: <ESC>I0 This escape code is the command to tell the printer to go to draft mode. The <Esc> must be created by a text editor that lets you embed control characters in text. With WordStar or SideKick, for example, you would type Ctrl-P <Esc>. In WordStar, this will show on-screen as ^[. If you type the file to the screen in DOS, the escape code will not show at all. With this line added to your batch file, if the printer is off when you exit the program, DOS will respond with a "Write fault error" and the standard "Abort, Retry, or Ignore" option. You can then choose the abort option or turn the printer on and choose retry instead. One simple extension of this method is to create a series of such batch files for different modes (NLQ, condensed, draft). Then you can conveniently switch between modes when printing ASCII files from DOS. Editor's Note: To take this one step further, you can create batch files that will set the printer mode and start printing with a single command. For example, if NLQ.BAT reads: TYPE NLQ.ASC > LPT1: TYPE %1 > LPT1: and NLQ.ASC contains the escape sequence for NLQ mode for your printer, then you can set the printer and start printing with the simple command NLQ filename To avoid surprises, you might want to choose a "standard" setting for the printer and add the appropriate command for that setting at the end of each batch file. ----------------------------------------------------------------- BASIC Batch Enhancements (PC Magazine Vol 5 No 22 Dec 23, 1986 User-to-User) This system creates a batch file that can access all of the subdirectories on your disk. The DIRSTART.BAT file searches the disk and writes a list of the subdirectory names into a file called DIRS.DAT. It then runs the DIRS.BAS program, which processes the contents of DIRS.DAT and creates the DIRS.BAT batch file. DIRS.BAT will contain each of your subdirectory names, preceded by two replaceable parameters, and will run commands across your entire disk, such as: DIRS DIR /W A similar program, DIRS2.BAS, works like DIRS.BAS except that it places the replaceable parameters in different places (the second goes after the subdirectory name), which allows wildcard directory searches and operations such as: DIRS2 DIR *.COM If you try DIRS2.BAS, be sure to change the last line in the DIRSTART.BAT batch file that runs it, from BASICA DIRS to BASICA DIRS2. The following are some illustrations of this technique: DIRS DSORT N uses one of the programs in The Norton Utilities to sort all subdirectories by filename, DIRS2 DIR *.DOC displays all of your .DOC filenames, DIRS2 DEL *.BAK deletes all of the .BAK files in all your subdirectories, and -- try this with caution -- DIRS2 DEL *.* erases all files but leaves your subdirectories intact. DIRSTART.BAT: echo off echo Processing disk .... chkdsk/v | find "Directory" > DIRS.DAT basica dirs rem Change to "basica dirs2" for DIRS2.BAS 100 'DIRS.BAS 110 DIM A$(256):DIM B$(256) 120 OPEN "DIRS.DAT" FOR INPUT AS #1 130 OPEN "DIRS.BAT" FOR OUTPUT AS #2 140 PRINT #2,"ECHO OFF" 150 LINE INPUT #1,A$ 160 B$=MID$(A$,11,40) 170 PRINT #2,"%1";" ";"%2";" ";B$ 180 IF EOF(1) GOTO 190 ELSE 150 190 CLOSE:SYSTEM 100 'DIRS2.BAS 110 DIM A$(256):DIM B$(256) 120 OPEN "DIRS.DAT" FOR INPUT AS #1 130 OPEN "DIRS2.BAT" FOR OUTPUT AS #2 140 PRINT #2,"ECHO OFF" 150 LINE INPUT #1,A$ 160 B$=MID$(A$,11,40) 170 PRINT #2,"%1";" ";B$; 180 IF LEN(B$)>3 THEN 200 190 PRINT #2,"%2":GOTO 210 200 PRINT #2,"\";"%2" 210 IF EOF(1) GOTO 220 ELSE 150 220 CLOSE:SYSTEM Editor's Note: Once you've used CHKDSK /V | FIND "Dir" > DIRS.DAT to create the list of subdirectories, rather than write a BASIC program you can use the search-and-replace mechanism of your word processor to create batch files such as the two mentioned here. This technique shows the real brute-force power of DOS, especially when it comes to replaceable parameters. Remember to have BASIC handy when you run these, or have it in a subdirectory that's included in your PATH. You can also use SWEEP.COM (PC Mag Vol 4 No 23) to do many of these jobs faster and more elegantly. ----------------------------------------------------------------- Don't Tread On Me (PC Magazine Vol 5 No 22 Dec 23, 1986 User-to-User) Software vendors often include an AUTOEXEC.BAT file on their distribution disks or provide an installation program that creates one. By merely copying the distribution disk (using COPY *.*) to your hard disk root directory or simply installing the program, you might wipe out your own carefully designed pre-existing AUTOEXEC.BAT file. Although installing each software package in its own directory can reduce this risk, the method is not foolproof. To eliminate the risk entirely, never use AUTOEXEC.BAT as the real name for the sequence of commands you want to execute on start-up. Since the AUTOEXEC.BAT file is no different from any other file except for its name, and since any .BAT file can execute another .BAT file, you AUTOEXEC.BAT file can contain one simple, easy-to-remember command: STARTUP.BAT. STARTUP.BAT contains all the commands that would normally be in AUTOEXEC.BAT. You never have to worry then about blowing away your start-up routines by overlooking an AUTOEXEC.BAT file on a distribution disk, or an installation program that creates its own. Furthermore, the name STARTUP.BAT itself is an obvious clue as to what AUTOEXEC.BAT should contain if you ever need to re-create it. Editor's Note: Some programs routinely corrupt both AUTOEXEC.BAT and CONFIG.SYS. It was once easy to spot this, since programs would install themselves through long batch files that you could read and change with a word processor. But many programs now use .COM and .EXE files to do the installation. Another elegant protection solution is to change COMMAND.COM so that it will look for a batch file with a name other than AUTOEXEC.BAT. In fact, the first file COMMAND.COM tries to execute doesn't even have to end in .BAT. To try this, make a copy of COMMAND.COM and type: DEBUG COMMAND.COM Find out how long your version of COMMAND.COM is by typing RCX and hitting the Enter key twice. DEBUG will respond by printing the letters CX and then the file's length in hex. For instance, in DOS 3.1, you'd see: CX 5AAA Then search for AUTOEXEC.BAT by typing in: S 100 5AAA "AUTO" (substituting the actual length for other versions of COMMAND.COM that DEBUG prints after the CX). DEBUG will then print the address of the beginning of the name AUTOEXEC.BAT, which in DOS 3.1 would look like: 5506:130F (Ignore the four hex numbers on the left; they'll vary from system to system, and they don't matter here.) AUTOEXEC.BAT is 12 characters long (11 for the filename and 1 for the period before the extension), so you have to remember to pad out the extra spaces if the new name you replace it with has fewer than 12 characters. To replace AUTOEXEC.BAT with STARTUP, under DOS 3.1 type: E 130F "STARTUP " To check your work, type: D 130F and make sure you've written over all traces of AUTOEXEC.BAT. To save the modified COMMAND.COM, type: W followed by: Q to end the DEBUG session. Then rename your old AUTOEXEC.BAT file to STARTUP and reboot. However, if you don't like changing COMMAND.COM, the next best safeguard is to keep a subdirectory called \BAKUP that contains your AUTOEXEC.BAT, COMMAND.COM, and CONFIG.SYS files. If new programs obliterate your old main startup files, you can always type: COPY \BAKUP\*.* \ ----------------------------------------------------------------- Aborting AUTOEXEC.BAT (PC Magazine Vol 5 No 22 Dec 23, 1986 User-to-User) Sometimes you don't want to run your hard disk AUTOEXEC.BAT. A combination of resident programs loaded by your AUTOEXEC.BAT might cause your machine to hang. Or you might not want to run a product your AUTOEXEC.BAT installs (for example, you might not want to bring up the PC Network before doing backups). In either case, one solution is to boot off a floppy disk in drive A:. Or you can continuously press Ctrl-Break while your machine is booting, hoping your AUTOEXEC.BAT will abort before the critical instructions occur. Either solution is fine if you run into the problem only once in a while, but neither is ideal. A far better solution is to use a small program called KBFLAG.COM to monitor your keyboard as you boot up and send a code to your AUTOEXEC.BAT file that an IF ERRORLEVEL instruction can trap. To create the KBFLAG.COM program, type in the following KBFLAG.SCR script, using the DOS COPY CON command or any pure-ASCII word processor: N KBFLAG.COM A MOV AX,40 MOV DS,AX MOV AL,[17] MOV AH,4C INT 21 RCX C W Q Be sure to leave a blank line above RCX and hit the Enter key at the end of each line, especially the last one. Once you install this program, you can press one single key while your machine is booting to avoid running your AUTOEXEC.BAT. Then, add these two lines at the very beginning of your AUTOEXEC.BAT: KBFLAG IF ERRORLEVEL 1 GOTO Note: The second statement is syntactically incorrect. When ERRORLEVEL is nonzero, you will get a message about a missing label (since the GOTO does not specify a label). Ignore the error message. The important thing is that the remainder of the .BAT file will not be executed. KBFLAG simply sets the DOS ERRORLEVEL to the value of the KBFLAG in the ROM BIOS area. You can use different keys to trigger KBFLAG. These keys, and the codes read by IF ERRORLEVEL, are: 1 = Right Shift 2 = Left Shift 4 = Ctrl key 8 = Alt-Shift 16 = ScrollLock 32 = NumLock 64 = CapsLock 128 = Ins For example, you can avoid running AUTOEXEC.BAT if you press and hold the Shift key while your machine boots, or if you simply press NumLock while your CONFIG.SYS is running. The latter technique is preferable in some situations. (Long CONFIG.SYS files can run for over a minute -- you wouldn't want to have to hold the Shift key down that long.) You can add the above key values together. For example, if you wanted the trigger to be the Right and Left Shift keys plus the Ins key (toggled on) you would use an ERRORLEVEL trap of 131 (1+2+128=131). You could also make your batch file test for several ERRORLEVELs or act differently when different keys are pressed. For example, CapsLock could mean abort the AUTOEXEC.BAT, while NumLock could do everything but load a couple of resident programs. Of course, KBFLAG can be used in any .BAT file, not just your AUTOEXEC.BAT. Editor's Note: Stopping the execution of a batch file by forcing a syntax error works, but there's a much simpler way to avoid running the batch file. Make the first two lines of your AUTOEXEC.BAT: KBFLAG IF ERRORLEVEL 128 GOTO :END and then add a line at the very end of the batch file: :END Then you can avoid running your AUTOEXEC.BAT file by toggling the Ins key when you boot up. KBFLAG will send a 128 to the IF ERRORLEVEL trap, which will branch to the :END label. This is far more elegant than pounding on the keyboard, which can generate 301 bootup errors and force you to hit the F1 key and then restart the whole operation. Using the Ins toggle means you can branch out of the program with one simple key press, or start normally by keeping your fingers off the keyboard. ----------------------------------------------------------------- AUTOEXEC Autopilot (PC World December 1986 Star-Dot-Star) A number of different computers, all configured differently, are used in an office. Some have two floppy drives, some have one, some have a hard disk, some do not. This AUTOEXEC.BAT file determines which drive letter refers to the RAM disk, so that the start-up process operates properly on every machine. The techniques relies on the fact that when the system is turned on, there are no files in the RAM disk. The first IF EXIST command tests for the presence of files on drive C:. If there are none, drive C: is the RAM disk. If a file is present, drive C: must be a hard disk, so the batch file branches to :isDhard and checks whether drive D: has any files. If there is no file, drive D: is the RAM disk; if there is, drive E: is the RAM disk. Once the drive letter of the RAM disk is determined, the batch file uses the SET command to assign that letter to a variable that can be used by other commands within the batch file. The following command uses that variable as the drive letter and copies a second batch file to the RAM disk. The second batch file contains the remainder of the start-up commands and executes from the RAM disk. When the first batch file transfers execution to the second, it passes the RAM disk drive letter on as a command line parameter for use by other commands within the second file. echo off cls if exist c:*.* goto isDhard echo No fixed disk present set ramdisk=C: goto :more :isDhard if exist d:*.* goto D echo Fixed disk is drive C: set ramdisk=D: goto more :D echo Fixed disk is drive D: set ramdisk=E: :more echo RAM disk is drive %ramdisk% copy a:autobat2.bat %ramdisk% >nul %ramdisk% autobat2 %ramdisk% Editor's Note: If you often use different PC's, and one has more than two hard disks or a hard disk that is divided into more than two volumes, you must notify AUTOBAT.BAT to also check those drives for files.