A Gazetteer and Dictionary
for DOS 6.22

Compiled by Randy D. Ralph, MLIS, Ph.D.

In place 1996.  Last updated on January 13, 2001.  Copyright © 1996 - 2002 NetStrider.
SAFE Commands DANGEROUS Commands SHORTCUT Keystrokes

Table of Contents
DOS Commands and System Files

ANSI.SYS EMM386.EXE MultiConfig
APPEND ERASE NLSFNC
ATTRIB EXIT NUMLOCK
Batch commands EXPAND PATH
BREAK FASTHELP PAUSE
BUFFER FASTOPEN POWER
CALL FC POWER.EXE
CD FCBS PRINT
CHCP FDISK PROMPT
CHDIR FILES QBASIC
CHKDSK FIND RAMDRIVE.SYS
CHKSTATE.SYS FOR RD
CHOICE FORMAT REM
CLS GOTO REN
COMMAND.COM GRAPHICS RENAME
CONFIG.SYS HELP REPLACE
COPY HIMEM.SYS RESTORE
COUNTRY IF RMDIR
CTTY INCLUDE SCANDISK.EXE
DATE INSTALL SET
DDBLSPACE INTERLNK SETVER
DEBUG INTERLNK.EXE SETVER.EXE
DEFRAG International commands SHARE
DEL INTERSERVR SHELL
DELTREE KEYB SHIFT
DEVICE LABEL SIZER.EXE
Device drivers LASTDRIVE SMARTDRV
DEVICEHIGH LH SMARTDRV.EXE
DIR LOADFIX SORT
DISKCOMP LOADHIGH STACKS
DISKCOPY MD SUBMENU
DISPLAY.SYS MEM SUBST
DOS MEMMAKER SWITCHES
DOSKEY MENUCOLOR SYS
DOSSHELL MENUDEFAULT TIME
DRIVER.SYS MENUITEM TREE
DRIVPARM MKDIR TYPE
DRVSPACE MODE UNDELETE
Drvspace Tips MORE UNFORMAT
DRVSPACE.SYS MOVE VER
ECHO MSAV VERIFY
EDIT MSBACKUP VOL
EGA.SYS MSCDEX VSAFE
EMM386 MSD XCOPY


ANSI.SYS

ANSI.SYS is a device driver that needs to be loaded when your computer starts up. It controls the display of fonts and colors, controls cursor movement, reassigns the functions of keys, and allows you to use ANSI escape sequences as embedded meta-commands within batch files to add color, change video modes, place text precisely on the screen, etc. For more detailed help on ANSI.SYS, type HELP ANSI.SYS at any DOS command prompt.

To activate ANSI.SYS you need to put a line in your CONFIG.SYS file, which resides in the DOS boot directory or root directory of your PC that tells your PC to load the driver whenever it is booted or turned on. (In Windows 95 you'll find CONFIG.SYS in the C:\WINDOWS\COMMAND directory) Use one of the two following lines to activate the driver:

DEVICE=ANSI.SYS
DEVICEHIGH=ANSI.SYS

The first statement loads ANSI.SYS into conventional memory, the second loads ANSI.SYS into high memory. Load the driver into high memory to save space for programs or drivers that require conventional memory.

NOTE: Unless you need the features provided by ANSI.SYS, don't load it. It will take up memory unnecessarily and could interfere with some other programs. If your PC is running Windows 95, for example, you don't need ANSI.SYS.


APPEND

APPEND allows a program to open data files in any directory on your PC as if the files were in the same directory as the one from which the program was started. NOTE: Don't use APPEND with Windows programs or from a DOS shell from Windows, it will crash your system. Appended directories are treated by the DOS system as if they were part of the current directory.

For detailed help on the APPEND command type HELP APPEND at any DOS command prompt.


ASCII

ASCII (American Standard Computer Information Interchange) code is used almost universally in PCs to display and control the placement of text on the screen and to provide a set of special characters for use in computer commands. Basically, a single ASCII code consists of 8 bits (8 on/off pulses - bits), 7 for data and 1 for parity. The 8 bit length allows for a total of 256 ASCII characters, including the standard alphabetic and numerical characters as well as a number of special signs, symbols and international characters. The table below provides a correspondence between ASCII designation and the character generated by the code.

ASCII Code Chart

(Characters displayed will depend on the font loaded)

Code Char. Code Char. Code Char. Code Char. Code Char. Code Char.
000 <nul> 044 , 088 X 132 176 ° 220 Ü
001 <soh> 045 - 089 Y 133 177 ± 221 Ý
002 <stx> 046 . 090 Z 134 178 ² 222 Þ
003 <etx> 047 / 091 [ 135 179 ³ 223 ß
004 <eot> 048 0 092 \ 136 ˆ 180 ´ 224 à
005 <enq> 049 1 093 ] 137 181 µ 225 á
006 <ack> 050 2 094 ^ 138 Š 182 226 â
007 <bel> 051 3 095 _ 139 183 · 227 ã
008 <bs> 052 4 096 ` 140 Œ 184 ¸ 228 ä
009 <tab> 053 5 097 a 141
185 ¹ 229 å
010 <lf> 054 6 098 b 142
186 º 230 æ
011 <vt> 055 7 099 c 143
187 » 231 ç
012 <np> 056 8 100 d 144
188 ¼ 232 è
013 <cr> 057 9 101 e 145 ' 189 ½ 233 é
014 <so> 058 : 102 f 146 ' 190 ¾ 234 ê
015 <si> 059 ; 103 g 147 " 191 ¿ 235 ë
016 <dle> 060 < 104 h 148 " 192 À 236 ì
017 <dc1> 061 = 105 i 149 193 Á 237 í
018 <dc2> 062 > 106 j 150 194 Â 238 î
019 <dc3> 063 ? 107 k 151 195 Ã 239 ï
020 <dc4> 064 @ 108 l 152 ˜ 196 Ä 240 ð
021 <nak> 065 A 109 m 153 197 Å 241 ñ
022 <syn> 066 B 110 n 154 š 198 Æ 242 ò
023 <etb> 067 C 111 o 155 199 Ç 243 ó
024 <can> 068 D 112 p 156 œ 200 È 244 ô
025 <en> 069 E 113 q 157
201 É 245 õ
026 <eof> 070 F 114 r 158
202 Ê 246 ö
027 <esc> 071 G 115 s 159 Ÿ 203 Ë 247 ÷
028 <fs> 072 H 116 t 160
204 Ì 248 ø
029 <gs> 073 I 117 u 161 ¡ 205 Í 249 ù
030 <rs> 074 J 118 v 162 ¢ 206 Î 250 ú
031 <us> 075 K 119 w 163 £ 207 Ï 251 û
032 <sp> 076 L 120 x 164 ¤ 208 Ð 252 ü
033 ! 077 M 121 y 165 ¥ 209 Ñ 253 ý
034 " 078 N 122 z 166
210 Ò 254 þ
035 # 079 O 123 { 167 § 211 Ó 255 ÿ
036 $ 080 P 124 | 168 ¨ 212 Ô
037 % 081 Q 125 } 169 © 213 Õ
038 & 082 R 126 ~ 170 ª 214 Ö
039 ' 083 S 127
171 « 215 ×
040 ( 084 T 128
172 ¬ 216 Ø
041 ) 085 U 129
173 ­ 217 Ù
042 * 086 V 130 174 ® 218 Ú
043 + 087 W 131 ƒ 175 ¯ 219 Û


ATTRIB

The ATTRIB command can be used to display or alter file characteristics. Files can be:

A Archived Fixed in location on the disk - unmovable.
H Hidden Can't be seen using the DIR command.
R Read Only Can't be deleted, moved or changed - only read or executed.
S System Fixed in location on the disk and marked as system files.

FORM:

ATTRIB +/-attribute1 +/-attribute2 . . . drive:\path\filename

WHERE:

attribute can be set to + = on or - = off.

drive:\path\ specifies and drive letter and path (optionally).

filename specifies the name of the file to change.

To switch a file attribute just precede the attribute with a + (plus) or - (minus) sign.

EXAMPLES:

ATTRIB -A -H -R -S VANILLA.FIL

would clear all the attributes for file VANILLA.FIL - make it vanilla-flavored.

ATTRIB +R SAFE.FIL

would make file SAFE.FIL read only so that it could not be accidentally changed or deleted.

ATTRIB +H RACY.PIC

would make file RACY.PIC invisible so that it could not seen using the DIR command.

For more detailed information on the ATTRIB command type HELP ATTRIB at any DOS command prompt.


Batch Commands

A batch file is a flat ASCII file - a text file - that contains a list of DOS commands. It must have the standard .BAT filename extension. A batch file can be executed by typing its name (with or without the .BAT filename extension) at the DOS command prompt. It is good policy to create a directory on your PC called C:\BAT which contains all the batch files you create yourself. The C:\BAT directory needs to be placed in the PATH= statement in your AUTOEXEC.BAT file so that DOS can find your batch files and execute them from a command entered at any location on your PC within the directory tree. When you enter the name of a batch file at the DOS command prompt, the commands contained within the batch file are executed in the order given and control is returned to DOS upon completion.

You can use any DOS command in a batch file that you could also use at the DOS command prompt. In addition, there are some DOS commands that were designed especially with use in batch files in mind:

CALL Runs another program or batch file and returns to the current batch file. IF Begins a conditional statement that allows branching to a labeled location based on the condition.
CHOICE Allows the batch file to branch to a labeled location based on a user choice. PAUSE Pauses execution of the batch file for a specified period of time.
ECHO Echoes text to the screen or hides the execution of batch file commands. REM Indicates a remark - remarks out a command.
FOR Begins a FOR/NEXT loop to be repeated. SHIFT Changes the location of changable parameters in the batch file.
GOTO Jumps to a labeled location with the batch file.
You can append the DOS command switch /Y to the end of a command to start up a batch file. This allows you to step through a batch file line by line during execution and selectively bypass or carry out each individual command line. This is very useful for debugging batch files - tracking down errors.


BREAK

The BREAK command sets or clears extended CTRL+C (break) checking. The command functions at the DOS command prompt or as a command line in the CONFIG.SYS file. Including the BREAK ON command in the CONFIG.SYS file extends checking every time the computer is booted or turned on. The CTRL+C keystroke combination is used to interrupt a program or an activity and is generally only read from the keyboard during input/output operations such as printing, screen display or interaction with the keyboard. Turning BREAK to the ON status allows DOS to extend CTRL+C interrupt checking to more kinds of activities. This is useful in that it gives the CTRC+C interrupt more power. The default is set to OFF. Only two forms of command syntax are acceptable:

BREAK ON
BREAK OFF


BUFFER

The BUFFER command is used within the CONFIG.SYS file to allocate memory for a specified number of buffers when the computer is booted or starts.

FORM:

BUFFERS=n1,n2

WHERE:

n1 = the number of disk buffers in the range from 1 to 99

n2 (optional) = the number of buffers in the secondary buffer cache in the range from 0 to 8.


CALL

The CALL command is used within a batch command file to start up another batch command file. CALL returns control to the original batch command file on successful completion of the called routines.

FORM:

CALL drive:\path\filename batch-parameters

WHERE:

drive:\path\filename

Specifies the location and name of the batch command file to run, including (optionally) the drive letter and full path to the called batch command file. The called batch command file must have the .BAT filename extension.

batch-parameters

Specifies (optionally) any command-line information required by the called batch command file.


CHDIR (CD)

The CHDIR, or CD command displays the name of the current directory or changes the current directory.

FORM and EXAMPLES:

CHDIR\dirname - changes to directory dirname.
CHDIR .. - moves up one level in the directory tree.
CD drive:\dirname - changes to the drive letter and directory specified.
CD\dirname - changes to directory dirname.
CD ..\dirname - moves up one level in the directory and then down to subdirectory dirname.

To display the current drive letter and directory name, use either CHDIR or CD without command parameters.


CHKDSK

The CHKDSK command is largely obsolete and has been replaced in its functionality by the SCANDISK.EXE program. CHKDSK checks the status of a physical disk and displays a status report. It is used to fix disk errors such as lost data strings and file allocation table errors. It also displays a brief summary of disk usage.

FORM:

CHKDSK drive:\path\filename /F /V

WHERE:

drive:\path\filename - (optionally) specifies the drive letter, path and file name to check.

Optional Switches:

/F
Checks for lost data chains and converts them to files in the root directory with extension .CHK.

/V
Forces CHKDSK to display the name and location of every file checked. This can be piped to a file.


CHKSTATE.SYS

A file used exclusively by MEMMAKER.EXE during memory optimization.


CHOICE

CHOICE is used only in batch command files to prompt the user to make a choice among several displayed options. CHOICE displays a prompt with options and pauses until the user chooses from among the set of displayed options. The batch command file branches to labeled subsections depending on the choice made.

FORM:

CHOICE /C:keys /N /S /T:default,secs text

WHERE:

text
Sets the explanatory text displayed before the user prompt (?). Quotation marks are necessary only a reserved character like the / (slash), used for switches is included. If no text is specified, CHOICE displays only the ? user prompt.

Optional Switches:

/C:keys
Specifies allowable key responses in the prompt. When displayed, the allowed keys will be separated by commas, will appear in brackets ([]), and will be followed by the ? user prompt. If no keys are specified in the the /C switch, CHOICE uses YN (yes/no) as the default. The colon (:) is optional in the prompt display.

/N
This switch turns off the user prompt. The text specified is still displayed before the prompt. Any keys specified as choices remain valid.

/S
This switch forces case sensitivity. Without this switch CHOICE will accept either uppercase or lowercase responses.

/T:default,secs
This switch pauses CHOICE for a specified number of secs, in the range from 0 to 99, before executing the specified default keystroke, itself.


CLS

The CLS command clears the screen and puts the cursor at the top.


COMMAND and COMMAND.COM

The COMMAND.COM program invokes the DOS command interpreter. For all intents and purposes, it is the DOS system. Issuing the COMMAND command (sic) at a system prompt or from within a batch command file starts a new instance of the command interpreter.

For more information on the command interpreter, see your DOS manual.


CONFIG.SYS

The CONFIG.SYS file is an important system file that must reside in your DOS root directory. It contains parameters and commands that set up the environment in which your computer works. It also initializes any special devices that your system requires and determines the way in which your computer will utilize memory.

The CONFIG.SYS file and its contents can be complex. For more information on the file, see your DOS manual.

A template for a minimal CONFIG.SYS file is displayed below:

        DEVICE=C:\DOS\ANSI.SYS
        DEVICE=C:\DOS\HIMEM.SYS
        DEVICE=C:\DOS\EMM386.EXE
        DOS=HIGH,UMB
        BUFFERS=20
        FILES=40
        BREAK ON


COPY

The COPY command copies one or more files to a location or file specified. The COPY command can also be used to concatenate files. When more than one file is copied, DOS displays the name of each file specified as it is copied.

See also the related command MOVE.

SIMPLE FORM:

COPY source destination

COMPLEX FORM:

COPY (switches) source (switches) destination (switches)

Copies the source file to the destination file using any switches provided. The destination can also include a complete path, including drive letter.

Optional Switches:

/A

Specifies that the files or destinations are ASCII (text) files. If placed before the source or destination it is used as the default until another switch overrides it. If placed after source and destination it applies to all files.

/B

Specifies that the files or destinations are binary files. If placed before the source or destination it is used as the default until another switch overrides it. If placed after source and destination it applies to all files.

/V

Placed at the end of the command, it specifies that all the files named should be verified as correctly copied.

/Y

Placed at the end of the command, it forces the command to copy over any file already existing that has the same name as the destination.

EXAMPLES:

COPY CON HOBBIT.TXT

This would copy whatever is typed onto the screen (CONSOLE) into a file called HOBBIT.TXT in the current directory. Copying is completed and the file written to disk when the user enters the CTRL+Z (end of input) keystroke combination followed by a carriage return (enter) keystroke to close and write the file.

COPY FILE1.TXT+FILE2.TXT+FILE3.TXT ALLFILE.TXT

Copies files FILE1.TXT, FILE2.TXT and FILE3.TXT to the single file ALLFILE.TXT. This concatenates all the source files into a single destination file.

COPY A:MYFILE.DAT D:\MYFILES /V /Y

Copies a file on disk drive A: to disk drive D: in directory MYFILES, verifies the copy and overwrites any existing files with the same name on the destination drive and directory.

The wildcard character can be used in the COPY command to specify multiple file names but must be used with caution:

COPY B:*.* *.* /Y

Copies all files on disk drive B: to the current directory and overwrites any files already existing in the current directory that have the same names.


CTTY

This command can be used to change the input devices that control and drive your computer, normally the keyboard, and the mouse or joystick. If control is attached to another device, such as a serial port, the computer can be controlled remotely, perhaps via modem.

See the DOS users manual for details of command syntax and program parameters.


DATE

The DATE command calls up a dialog that allows you to specify the date held in the computers nonvolatile memory. If the date your computer is assigning to files is incorrect this command allows you to correct the date parameter.


DBLSPACE

This is a driver system that was used to double the disk storage space in computers prior to DOS 6.22 by compressing stored data. It has been replaced by the DRVSPACE system.


DEBUG

Runs the Debug program - a testing and editing tool. DEBUG [[drive:][path]filename [testfile-parameters]]

  [drive:][path]filename  Specifies the file you want to test.
  testfile-parameters     Specifies command-line information required by
                          the file you want to test.
After Debug starts, type ? to display a list of debugging commands.


DEFRAG.EXE

The DEFRAG program can be run interactively or in command mode from a batch file with command switches set. The program scans the directory structure and file allocation tables and optimizes the file structure of the disk specified. Your machine's performance will be enhanced by periodic use of the DEFRAG program to clean up and reorganize your hard disk. This program cannot be run from Windows.


DEL - ERASE

The DEL command deletes or erases a specified file or object from the disk. A full path to the file to be deleted can be included.

FORM and EXAMPLES:

DEL A:\NASTY.GIF

This would delete file NASTY.GIF from the root directory of disk drive A:.

DEL D:\EXCEL\*.* /Y

This would delete all files from the EXCEL directory on disk drive D: without confirmation.

ERASE *.*

This would delete all files in the current directory. The system will prompt the user for confirmation before proceeding.

If wildcards () are used, the system will prompt for confirmation before deleting the files specified unless the /Y (yes) switch is used. Use wildcard characters with caution when deleting files and pay attention to system confirmation messages, if any.


DELTREE

This command will remove a specified directory and all its subdirectories from the disk. WARNING: This command is difficult to reverse or recover from if used incorrectly or inadvertently. Use it with extreme caution.

FORM and EXAMPLE:

DELTREE WINDOWS /Y

This would delete the WINDOWS directory from the current disk drive along with all its files and subdirectories. The /Y switch would perform the delete without any further prompting from DOS. If the switch is not used, the system will prompt the user for verification of the delete. The command cannot be issued within the directory to be removed but must be issued from the directory level just above it.


DEVICE and DEVICEHIGH

Used only in the CONFIG.SYS file, this command loads a specified device driver into conventional memory when the computer is booted or started up. Device drivers power your PC's peripherals and set up the DOS environment. The corresponding DEVICEHIGH command loads the specified device driver into high memory. This allows other device drivers or programs more room in conventional memory.


DIRECTORY (DIR)

The DIR command displays the files and subdirectories present in a specified directory on a specified drive.

FORM:

DIR drive:\path\filename /switches

WHERE:

drive: - optionally specifies the disk drive letter.

\path - optionally specifies the directory path.

filename - optionally specifies the file(s) to display.

Optional Simple Switches:

/B

Forces the directory display to show only one file or subdirectory name per output line.

/L

Specifies that the filenames be displayed in lowercase. Uppercase display is the default.

/P

Specifies that the display, if longer than one screen, should pause at the end of each screen of information displayed and wait for confirmation to go on to the next screen from the user.

/S

Displays all files specified in every subdirectory beneath the current directory. This is useful for searching the disk for a specific file name.

/W

Specifies that the directory display should be in the brief format and displayed wide across the screen.

Optional Complex Switches:

/A - attributes /C - compression /O - sorting order.

Read your DOS manual or type HELP DIR at a command prompt to read more about these switches.

EXAMPLES:

DIR

Produces a simple directory display of all files and subdirectories in the current directory.

DIR A:\*.GIF /L /W > C:\TEMP\IMAGES.TXT

Generates a wide directory display of all files with extension .GIF that are in the root directory of drive A: and sends the output to a disk file called IMAGES.TXT on disk drive C: in directory TEMP.


DISKCOMP

This command permits the user to compare the contents of two floppy diskettes for differences track by track based on the format and organization of the first diskette in the comparison.

FORM:

DISKCOMP drive1: drive2: /1 /8

WHERE:

drive1:
Optionally specifies the drive containing the first floppy diskette.

drive2:
Optionally specifies the drive containing the second floppy diskette.

Optional Switches:

/1
Compares only one side of the diskettes even if they are double-sided.

/8
Compares only the first 8 sectors per track even if more are available.


DISKCOPY

This command copies the entire content of a source floppy diskette to a target floppy diskette track by track based on the formatting of the source floppy and overwrites any information on the target floppy.

FORM:

DISKCOPY source: target: /1 /M /V

WHERE:

source:
Specifies the drive containing the source diskette.

target:
Specifies the drive containing the target diskette.

Optional Switches:

/1
Copies only the first side of the diskette.

/M
Requires the program to use only conventional memory to store diskette information temporarily during transfer.

/V
Verifies that all information is copied correctly from one diskette to another.


DISPLAY.SYS

This system driver allows the system to display international character sets on most color monitors. The driver must be loaded within the CONFIG.SYS file.

See also the discussion on International Commands.


DOS

This command is used only in the CONFIG.SYS file. It governs where the operating system is loaded into memory and how it maintains its links to memory while running programs.


DOSKEY

This command can be input from the keyboard at a system prompt but is usually invoked from the AUTOEXEC.BAT startup file. It loads a keystroke memory program which allows the user to recall previously issued commands with the up arrow on the keypad and edit them so that they can be repeated or modified and reentered with different parameters. The program requires about 3K of conventional memory and remains resident. It is of a type referred to as TSR (Terminate and Stay Ready or Terminate and Stay Resident).

FORM:

DOSKEY /REINSTALL /BUFSIZE=size /M /H /INSERT/OVERSTRIKE macroname=command_text

Optional Switches:

/REINSTALL
Reinstalls a new copy of the program in memory even if it's already been loaded.

/BUFSIZE=size
Specifies the size of the buffer the program uses to store previous commands. The default is 512 bytes.

/M
Displays all macros associated with DOSKEY.

/H
Display a history of all commands stored in the buffer and can be redirected to a file for processing as a batch command file.

/INSERT or OVERSTRIKE
Starts the program so that commands can be edited in overstrike or insert mode. The default is overstrike. Insert is more useful.

macroname=command_text
Creates a command macro with name macroname and commands command_text.


DOSSHELL

The graphical interface refered to as the DOSSHELL is not bundled with DOS 6.22. It was a menu-driven interface to the operating system.


DRIVER.SYS

This disk driver system must be installed within the CONFIG.SYS file. It creates a logical drive on the hard disk that can be used in the place of a physical floppy disk drive.

See the DOS users manual for details of command syntax, system and program parameters.


DRIVPARM

This command must be placed in the CONFIG.SYS file. It defines parameters for physical devices such as disk and tape drives when the operating system starts up. It modifies the characteristics of an existing disk drive and is used to override the driver definitions for any previously set up block device.

See the DOS users manual for details of command syntax, system and program parameters.


DRVSPACE and DRVSPACE.SYS

This utility can be used to compress data storage on the hard disk or floppies using the DRVSPACE.SYS system driver with must be installed in the CONFIG.SYS file. Nowadays, most high-end PCs have enough disk space to make the use of this compression system thoroughly unnecessary.

See the DOS users manual for details of command syntax, system and program parameters.


ECHO

This command is used primarily in batch command files as a means to enable or disable command echoing to the screen. The only command parameters are:

ECHO ON
ECHO OFF
ECHO text

Echoing can be turned on or off (enabled or disabled). A text message can be echoed to the screen from a batch command file. If this is coupled with ANSI codes, color, style and placement of text on the screen can be manipulated.

The ECHO OFF command can, itself, be hidden from view from within a batch command file by using the following form:

@ECHO OFF


EDIT

This command invokes the DOS screen editor.

FORM and EXAMPLE:

EDIT A:\PROGS\DOUBLE.BAS

Invokes the editor and loads file DOUBLE.BAS from directory PROGS on disk drive A: for editing.


EGA.SYS

This system driver saves and restores the screen display when the DOS Shell Task Swapper is used with simple EGA monitors. If your computer system has an EGA monitor this driver must be installed within the command in the CONFIG.SYS file.


EMM386.SYS

The expanded memory system, EMM386.SYS, gives your computer access to the upper memory area, beyond the conventional 640K, that all microcomputers still use. It is generally used in combination with the HIMEM.SYS driver.

EMM386.SYS allows the computer to use it's hard disk drive as extended memory to simulate expanded memory. It also allows you to load programs and other system drivers into upper memory blocks (UMB).

EMM386.SYS is a device driver and must be loaded when the PC boots up or is started using the DEVICE command in the CONFIG.SYS file. Only microcomputers with an 80386 microprocessor, or better, can use EMM386.SYS.

See your DOS users manual for command syntax and parameters.


ERASE

See the DEL command.


EXIT

This command quits the DOS command interpreter and returns control to the program from which DOS was called - Windows, for example.


EXPAND

This command expands a compressed program file. It can be used to retrieve and expand compressed program files from the DOS setup diskettes.

See the DOS users manual for details of command syntax and program parameters.


FASTHELP

This command, used by itself, gives a condensed list of all available DOS commands. If used in conjunction with a command name it provides a shortened version of the help available on that subject. See also HELP.


FASTOPEN

This command can be invoked in the AUTOEXEC.BAT or installed in the CONFIG.SYS file. It helps the system to open frequently used files more rapidly. For more information on the complex command parameters enter HELP FASTOPEN and any command prompt. FASTOPEN cannot be run from Windows.


FC

This command is used to compare the contents of two files for similarities and differences.

FORM:

ASCII Comparisons -

FC /A /C /L /LBn /N /T /W /nnnn drive1:\path1\filename1 drive2:\path2\filename2

Binary Comparisons -

FC /B drive1:\path1\filename1 drive2:\path2\filename2

WHERE:

drive, path and filename are optional and specify the two files for comparison. If not supplied the system prompts for the information.

Optional Switches:

/A
Abbreviates the output from an ASCII comparison.

/B
Forces a binary comparison.

/C
Ignores upper- and lowercase when making ASCII comparisons.

/L
Compares the files line by line and attempts to resynchronize when differences are encountered.

/LBn
Sets the number of lines n allowed in the line buffer. If the number of differing lines exceeds this number, the comparison is cancelled. The default is 100 lines.

/N
Displays line numbers during the comparison.

/T
Prevents tabs from being converted to spaces.

/W
Compresses the white space - consecutive spaces - to one space for comparison.

/nnnn
Specifies the number nnnn of lines that must be the same for resynchronization to have worked.

EXAMPLES:

FC FILE1.TXT FILE2.TXT
FC /B PROG1.EXE PROG2.EXE

Most of the optional switches are unnecessary in common comparisons.


FCBS

This command is used only in the CONFIG.SYS file. It specifies the number of file control blocks (FCBS) that the operating system can have open at one time. A file control block is a data storage area that contains information about a file and its characteristics.

See the DOS users manual for details of command syntax and parameters.


FDISK

This commmand starts the FDISK program. This program is used to configure the hard disk for use with DOS. It can be used to display and alter hard disk configuration, including add, delete and reconfigure hard disk partitions.

WARNING: The FDISK program must be used with extreme caution since it exercises great control over the structure and functionality of the hard disk.

You can request FDISK to display current hard disk parameters by using the FDISK /STATUS. This command is basically harmless, as it is only informational in character and does not really invoke the full FDISK capability.

See the DOS users manual for details of command syntax and parameters.


FILES

This command is used only in the CONFIG.SYS file. It specifies the number of files that can be opened at one time. The maximum value is 255.


FIND

The FIND command searches for a specified text string in a file or group of files. When the search is complete the program displays any lines of text that contained strings that matched the specified search text.

FORM:

FIND /V /C /N /I "string" drive:\path\filename . . .

WHERE:

"string"

Specifies the text string to search for. It must be enclosed in quotation marks.

drive:\path\filename

Specifies the location and name of the file(s) to search for the text string. Wildcards can be used in filenames.

Optional Switches:

/C
Displays only a count of the lines found that contain the search string.

/I
Allows the search to precede without regard to case.

/N
Gives the number of the lines found in each file searched.

/V
Displays all the lines found that do not contain the search string.

EXAMPLE:

FIND /I "everywhere" C:\DOCS\*.TXT

Searches all files in directory DOCS on drive C: with extension .TXT for occurrences of the text search string "everywhere" without regard to case.


FOR

This command begins a batch command file loop. It will execute a set of batch file commands repeatedly until a condition set by a variable is met.

See your DOS manual for syntax and command paremeters.


FORMAT

The FORMAT command prepares a disk for use with the DOS system. Unformatted disks cannot be read or written to by the system.

The command creates a root directory and establishes an empty file allocation table FAT for the directory structure. It checks the disk for bad sectors and marks them so that they cannot be used by the system.

WARNING: The FORMAT command is destructive. It will destroy all data on a disk which has been formatted and used previously. This is very difficult to recover from or undo without the appropriate disk utilities. Use FORMAT with caution.

The UNFORMAT command can be used to recover from an accidental diskette format, with some difficulty, but only if the /U optional switch has not been used and previous formatting information has been saved.

FORMS:

FORMAT drive: /V:label /Q /U /F:size /S /C
FORMAT drive: /V:label /Q /U /T:track /N:sector /S /C
FORMAT drive: /V:label /Q /U /1 /4 /S /C
FORMAT drive: /Q /U /1 /4 /8 /S /C

WHERE:

drive:
Specifies the letter of the disk drive to be formatted. This can be a hard disk or a floppy diskette.

Optional Switches:

/1

Instructs the program for format a diskette as single-sided.

/4

Instructs the program to format a 5¼-inch disk as 360K, double-densidy, double-sided on a 1.2MB diskette drive. This may not proceed reliably.

/8

Instructs the program to format a 5¼-inch disk with 8 sectors per track for backward compatibility to DOS 2.0.

/C

This switch forces FORMAT to retest any clusters which have been previously marked as bad.

/F:size

This switch lets the FORMAT program know the size of the diskette being formatted. It adjusts the number of sectors per track accordingly. Acceptable values for the size parameter are:

    160  - 160K,   single-sided, double-density,     5¼-inch disk
    180  - 180K,   single-sided, double-density,     5¼-inch disk
    320  - 320K,   double-sided, double-density,     5¼-inch disk
    360  - 360K,   double-sided, double-density,     5¼-inch disk
    1200 - 1.2MB,  double-sided, quadruple-density,  5¼-inch disk

    720  - 720K,   double-sided, double-density,     3½-inch disk
    1440 - 1.44MB, double-sided, quadruple-density,  3½-inch disk
    2880 - 2.88MB, double-sided, extra-high-density, 3½-inch disk

Although adjusting the size of the formatted diskette generally works, the diskette may not be transportable to another microcomputer reliably.

/N:sector and /T:track

Used in combination the /N:sector and /T:track switches controls the number of sectors per track. It is only necessary to use these switches when you need to format a disk in some special way. The /F:size switch is generally preferrable.

/Q

This switch performs a quick format. The disk is presumed to have no bad sectors and simply replaces any existing file allocation table.

/S

This switch transfers the DOS operating system files to the disk being formatted and makes it bootable. Only critical system files are transferred. If this switch is not used during formatting, it may be difficult to transfer the system to the diskette later because space may not be available for it in the first few sectors where it needs to reside.

/U

This switch formats the target disk or diskette unconditionally; that is, if there is already data present on the target it is destroyed without a confirmation prompt and without saving UNFORMAT information.

WARNING: If this switch is used the diskette is formatted unconditionally; that is, no previous formatting information is saved and the disk cannot be unformatted to recover lost data.

/V:label

This switch will write a disk volume label of up to 16 characters long on the disk which identifies it each time a directory is requested. This is useful for archival purposes. This switch is incompatible with the seldome-used /8 switch.


GOTO

This command is used exclusively in batch command files to allow the batch process to branch to a specified location, usually dependent on some sort of conditional test.

FORM:

GOTO label

EXAMPLE:

GOTO end

Instructs the system to jump to the location within the batch command file labeled end.


GRAPHICS

This command loads a memory-resident program that allows the system to dump screen displays to the printer. It can only be used if the system has a CGA color monitor or better.

For a detailed description of the command and its use and parameters see your DOS system manual.


HELP

This command invokes the DOS help facility and files. It can be used alone - which calls up the full screen version of the facility with index - or it can be used in combination with the command for which help is need - which calls up only that command's information screens.

EXAMPLES:

HELP /H
HELP ERASE

Optional Switches:

/B
Forces a monochrome display.

/G
Forces the fastest update rate for a CGA screen.
/H
Forces the system to display the maximum number of lines possible.


HIMEM.SYS

This system driver manages extended memory and is generally loaded as a companion to EMM386.SYS. It coordinates the use of extended memory, including the high memory area (HMA), so that no applications or device drivers attempt to use the same memory areas at the same time.

Generally, HIMEM.SYS is loaded from within the CONFIG.SYS file using the DEVICE command. This allows the system to load the driver when it is booted or at start up.

For more detailed information on HIMEM.SYS, see your DOS system manual.


IF

The IF command is used exclusively in batch command files. It begins a conditional test that may be used by the batch command file to branch based on the condition tested.


INCLUDE

The INCLUDE command is used exclusively in the CONFIG.SYS file for defining multiple boot configurations. Multiple boot configurations require that a menu be defined within the CONFIG.SYS file which appears when the computer boots or starts up. Every menu item displayed corresponds to a block of commands called a configuration block, in the CONFIG.SYS file.

For more detailed information on the INCLUDE command, see your DOS user manual.


INSTALL

The INSTALL command is used exclusively in the CONFIG.SYS file to install system components and programs.

For more detailed information on the INSTALL command, see your DOS user manual.


INTERLNK and INTERSRVR

This program connects two computers through their respective parallel or serial ports and enables them to share disk drives and printer ports. The INTERLNK.EXE device driver must be INSTALLed (above) in the CONFIG.SYS file before the command can be used.

The related INTERSRVR command also needs to be installed in the CONFIG.SYS file. This program starts the INTERLNK server that permits the two machines to communicate with one another.

For more detailed information on the INSTALL, INTERLNK and INTERSRVR commands, see your DOS user manual.


International Commands

The following commands are used to change country-specific settings and character sets within the CONFIG.SYS file:

CHCP - COUNTRY - KEYB - NLSFUNC

Your PC is already set up for standard American English functionality of you purchased it within the United States or Canada.

See also the DISPLAY.SYS driver.

If you need to know more about these commands see your DOS user manual.


LABEL

The command is issued from any system prompt and is used to change the volume label for the current disk or diskette.

EXAMPLE: LABEL BOOT_DISK

Changes the current volume label of the selected disk drive to BOOT_DISK.


LASTDRIVE

Used exclusively within the CONFIG.SYS file this command specifies the maximum number of drives that can be accessed depending on the drive letters assigned.

FORM:

LASTDRIVE=driveletter

WHERE:

driveletter
Represents the letter of the last valid drive that the system can address.


LOADHIGH

The LH command is used only in the CONFIG.SYS file. It loads a program into the upper memory area. Loading a program into the upper memory area preserves conventional memory for other programs.

For more detailed information about this command see your DOS user manual.


LOADFIX

This command is used as a prefix when loading programs. It forces the program's memory stack to be loaded above the first 64K of conventional memory. This ensures that the program will not POKE any commands into memory reserved for the operating system.

For more detailed information about this command see your DOS user manual.


MEM

This command displays the amount of used and free memory on the system. It can be used to display information about allocated memory areas, free memory areas, and programs that are currently loaded into memory.

FORM:

MEM /C|D|F|M modulename /P

Optional Switches:

The /C - /D - /F - /M optional switches are mutually exclusive.

/C

Lists the programs that are currently loaded into memory and shows how much conventional and upper memory each program is using. With this switch the program also summarizes overall memory use and lists the largest free memory blocks.

/D

Lists the programs and internal drivers that are currently loaded into memory. This is useful for debugging programs that are causing memory problems.

/F
Shows the free areas of conventional and upper memory and the the segment address and size of each free area of conventional memory. It shows the largest free upper memory block in each region of upper memory.

/M programname
Shows how a program module programname is currently using memory. It lists the areas of memory the specified program module has allocated and shows the address and size of each area.

/P

Pauses after each screen of output and prompts you to continue the display.


MEMMAKER

This command starts the DOS MemMaker program, which optimizes the computer's memory by moving device drivers and memory-resident programs to upper memory. To use MemMaker, the computer must have an 80386 or 80486 processor and extended memory. The program reboots the computer and tests a variety of memory configurations for optimal performance. It modifies system files AUTOEXEC.BAT and CONFIG.SYS which set up the system environment whenever the computer is booted or started.

For more detailed information about this command see your DOS user manual.


MENUCOLOR - MENUDEFAULT - MENUITEM

These commands are used exclusively in the CONFIG.SYS file. They set up the colors used by the menu system defined in the file, the default conditions used by the menu system and the menu items displayed in the menu system.

For more detailed information about these commands see your DOS user manual.


MKDIR (MD)

The MD command creates a directory or subdirectory on the specified disk and in the specified location within the existing directory tree.

FORM:

MKDIR drive:\path\dirname
MD drive:\path\dirname

WHERE:

drive:
Optionally specifies the letter of the drive on which the directory will be created.

\path
Optionally specifies the existing path directory name within which to create the new subdirectory.

dirname
Specifies the name of the new directory or subdirectory.

See also the related directory commands:

CHDIR - DIR - RMDIR


MODE

The MODE command is used to configure a variety of system devices. It can perform many different tasks, such as displaying system status, changing system settings, and reconfiguring or reassigning system ports and devices.

Because the MODE command performs so many different functions, the form of the command needed to carry out each task is quite different. Below is a list of tasks for which the command can be used:

  • Reconfiguring a printer attached to a parallel port (LPT1, LPT2, or LPT3) for printing at 80 or 132 characters per line, 6 or 8 lines per inch, or both (if the printer supports these features).

  • Configuring the baud rate, parity, and number of data bits and stop bits of a serial port (COM1, COM2, COM3, and COM4) for use with a specific printer, modem, or other serial device.

  • Displaying the status of all devices or of a single device.

  • Redirecting printer output from a parallel port to a serial port so that the serial port becomes the system's default printer port.

  • Preparing devices for character set (code page) switching.

  • Selecting another display adapter or changing the configuration of the current display adapter.

  • Setting the keyboard's autorepeat rate.

The MODE command cannot complete some tasks unless the ANSI.SYS and DISPLAY.SYS drivers have been installed in the CONFIG.SYS file.

For more detailed information about all the functions preformed by the MODE command see your DOS user manual.


MORE

The MORE command displays ouptut from a file one screen at a time with prompting for additional screens of information.

FORMS:

MORE < drive:\path\filename
command-name | MORE

WHERE:

< drive:\path\filename

Optionally specifies the location and name of the file to be displayed a page at a time to be piped to the screen using the < redirection.

command-name |

Specifies the command which will send data to the screen.

See also the related commands DIR and TYPE.


MOVE

This command moves one or more files from one specified location to another. The command can also be used to rename directories by "moving" them.

FORM:

MOVE /Y|-Y drive:\path\filename,[drive:\path\filename ... target

WHERE:

drive:\path\filename target

Specifies the names and locations of the files which will be moved to the target. Multiple files can be moved at one time but this can be confusing and is dangerous.

WARNING:

Use extreme caution with the MOVE command. If the target destination does not exist the system may erase the files you were trying to move. It is not possible to recover from this kind of error.

Consider using the related COPY command, instead. It is non-destructive of the original files.

Optional Switches:

/Y

Indicates that you wish the files to be moved without confirmation. This can be dangerous.

/-Y

The command will prompt you for confirmation if the commanded move would overwrite existing files in the target directory.


MSAV

The MSAV command calls up a program that will scan the computer's hard disk or floppies for known viruses. The trouble is that there are new viruses springing up all the time. The program cannot protect against viruses that it does not know how to detect. It can clean those it does find off your system.

For more detailed information about this command see your DOS user manual.


MSBACKUP

The MSBACKUP program allows you to specify which of the files and directories on your computer system you would like to back up to floppy diskettes or other storage devices. It is good policy to back up your computer once shortly after it has been set up and is running well and to save this initial backup in a safe place against the day it is needed. It is also good policy to perform incremental backups on a regular basis so that newer files and directories are saved, as well.

For more detailed information about this command see your DOS user manual.


MSCDEX

This is a program that can be loaded interactively from the keyboard or from within the AUTOEXEC.BAT file. The program uses the parameters supplied to locate and initialize any CDROM devices that are installed on your computer so that they can be used by the system. Generally, it is started from the AUTOEXEC.BAT file. The correct driver for your particular CDROM device must be properly installed in the CONFIG.SYS file.

For more detailed information about this command see your DOS user manual.


MSD

The MicroSoft Diagnostic program MSD is used to check your system for configuration and operational errors. The program can be launched either from your AUTOEXEC.BAT file or from the keyboard interactively. Based on the switches set, the program can produce detailed reports on a number of system parameters and settings.

For more detailed information about this command see your DOS user manual.


NUMLOCK

This function controls whether or not the NumLock key on the keyboard's numeric keypad is set to ON or OFF when the computer is booted or started. This can be set only in the CONFIG.SYS file.


PATH

The PATH statement can be issued either from the keyboard interactively or from within the AUTOEXEC.BAT file so that it is executed each time the computer is booted or started. The PATH statement determines which directories the system searches when it is asked to load or run a program or system file. Excessively long PATH statements used to be a problem on older machines because they limited the amount of environment space available to the system, but this is less of a problem on the newer, more powerful machines.

FORM:

PATH drive1:\path1;drive2:\path1;drive2:\path2 ...

WHERE:

drive(n):\path(n)

Specifies the drive letter and directory names of the paths to include in the search.

EXAMPLE:

PATH C:\;C:\BAT;C:\DOS;C:\WINDOWS;C:\

This PATH statement would permit the system to search the directories C:\ [root] - BAT - DOS - WINDOWS every time a command was issued that activated a program or system file.

The PATH statement can include a multiple of disk drives and directory names.


PAUSE

This statement is used only in batch command files. It causes the execution of the command file to stop and displays a message prompting the user to press a key to continue. This is generally used to allow users to have sufficient time to read menu options or displayed text.


POWER

This command turns the power conservation system on and off and configures it. The power management system reports the status of power management, and sets levels of power conservation for your computer. The system is governed by the POWER.EXE program which needs to be installed in the CONFIG.SYS file.

For more detailed information about this command see your DOS user manual.


PRINT

This command is used to send information contained within a data file to the system printer. The command can operate in the background since it creates a printer queue. Although the basic command is very simple:

PRINT filename

where filename is the name of the file to be printed, there is also a great deal of complexity and variety of forms of output that can be invoked using a number of special switches and command parameters.

See the DOS users manual for details of command syntax and program parameters.


PROMPT

This command can change the appearance of the system command prompt. The command prompt can be customized to display any text desired, including such information as the name of the current directory. This is a very helpful means of identifying your place in the directory tree at any given time.

FORM:

PROMPT text

WHERE:

text

Specifies all the text and information to be included in the new system prompt.

The following list shows the character combinations that can be used in the text parameter:

$B | (pipe)
$D the current date
$E <esc> (escape)
$G > (greater-than sign)
$H backspace (to hide the last character in the prompt)
$L < (less-than sign)
$N the current drive
$P the current drive and path
$Q = (equal sign)
$T the current time
$V the DOS version number
$$ $ (dollar sign)
$_ <cr><lf> (enter,line feed)

EXAMPLE:

PROMPT $P$G(space)(space)

Produces a command prompt that might look like this:

C:\WINDOWS> [you would enter your command here]


QBASIC

This command invokes the DOS QBASIC command editor. The program allows you to write and execute programs written in the BASIC computer language.


RAMDRIVE.SYS

This system driver can use part of the computer's random access memory (RAM) to act in the place of a physical hard disk drive. The driver must be loaded in the CONFIG.SYS file so that it is mounted when the system starts or is booted. A RAMDRIVE can greatly increase the speed of some often repeated disk read/write operations and can be configured as the default for these operations.

See the DOS users manual for details of command syntax and system parameters.


RMDIR (RD)

This command removes (deletes) a directory or subdirectory from the system's file allocation table and physically from the specified drive. The directory must be emptied of files beforehand.

FORMS:

RMDIR drive:\dirname
RD drive:\dirname

WHERE:

drive:\dirname

Specify the drive letter and the name of the directory or subdirectory to be deleted.

See the related command MKDIR.


REM

This command is used in system files and batch command files to "remark out" lines or to insert remarks into such files. The system takes no action on a command line that is preceded with the REM command.


RENAME (REN)

The REN command is used to rename a file or files. The command cannot be used to move files or to rename files across drives. If the destination name is already in use the command fails.

FORMS:

RENAME drive:\path\sourcename targetname
REN drive:\path\sourcename targetname

WHERE:

drive:\path\sourcename

Specifies the name and location of the file to be renamed. The drive letter and path are optional.

targetname

Specifies the name the file will be renamed to.

Multiple files cannot be renamed at one time. Wildcards (*) are allowed but the results can be unexpected. Use of wildcards is not recommended with this command.


REPLACE

This command is used to replace files in a target directory with file in a source directory that have the same names. The command can also be used to add unique filenames to the target directory.

FORM:

REPLACE sourcedrive:\sourcepath\sourcefiles targetdrive:\targetpath /A /P /R /W /U

WHERE:

sourcedrive\sourcepath\sourcefiles

Specifies the location and names of the source file or set of source files. Wildcards (*) can be used.

targetdrive:\targetpath

Specifies the location of the target destination drive and path and files or file set. The target filenames cannot be specified.

Optional Switches:

/A
Adds new files to the destination directory instead of replacing existing files This switch cannot be used with the /S or /U switch.

/P
Prompts for confirmation before replacing a target file or adding a source file.

/R
Replaces read-only files as well as unprotected files.

/S
Searches all subdirectories of the destination directory and replaces matching files. The /S and /A switches are incompatible.

/U
Carries out all replaces unconditionally without confirmation.


RESTORE

This is a command provided for backward compatibility with any older version of DOS. The command invokes the restore utility which can recover files from information backed up to floppy diskettes.

It has been replaced with the MSBACKUP program.


SCANDISK

This command invokes the DOS ScanDisk software. This software system can be used to analyze the hard disk or floppies for errors and can be configured to correct or report on any errors it finds. It is good policy to use the ScanDisk utility periodically to keep the computer's hard disk in top condition. A well-organized and groomed hard disk improves the overall performance of your microcomputer.


SET

This command is used to set system variables and set up system parameters within the AUTOEXEC.BAT file and batch command files.

FORM:

SET variable=string

WHERE:

variable and string

Specify the variable to be set and the value string to which it should be set.

This looks simple, but there are a great number of system features that can be set using this command.

See the DOS users manual for details of command syntax and parameters.


SETVER and SETVER.EXE

This command is used to display the DOS version table. It can report a version number for versions earlier than 6.0 to programs or device drivers that are incompatible with higher versions of DOS and require earlier versions to function properly. Even setting the version may not be enough to get some older programs to function in newer versions of DOS. It may be necessary for you to keep and use boot diskettes for older versions.

The SETVER.EXE program must be loaded in the CONFIG.SYS file if downward compatibility to older versions is desired at every boot or start up.

See the DOS users manual for details of command syntax and command parameters.


SHARE

This command is generally included in the AUTOEXEC.BAT file. It starts the SHARE program which monitors file sharing and dynamic locking and allocation capabilities on all disks and networked drives. This disallows simultaneous access to the same file by programs which might otherwise engage in a tug-of-war over the file or overwrite each other's changes to the file and destroy your work. The program can become annoying in some Windows applications which refuse to release control of files even when finished with them.

See the DOS users manual for details of command syntax and command parameters.


SHELL

This command must be executed within the CONFIG.SYS file. It specifies the name and location of any alternate command interpreter to be used in the place of the standard COMMAND.COM. This is useful in some instances where alternate command interpreters purchased to provide additional system security are desired.

See the DOS users manual for details of command syntax and command parameters.


SHIFT

This command is used exclusively within batch command files. It shifts the order of replaceable parameters %0 through %9. This can be useful for executing a number of commands as a group.

See the DOS users manual for details of command syntax and command parameters.


SIZER.EXE

A program used exclusively by the DOS MemMaker program. It is used to compute the optimum memory parameters while the program is running and is then removed from all system files.


SMARTDRV

This command starts and can be used to configure the SMARTDrive software which creates and manages the disk cache used for extended memory. Although it can be invoked at the command prompt, the program is generally run from within the AUTOEXEC.BAT file so that it intitalizes at every boot and start up.

See the DOS users manual for details of command syntax and command parameters.


SORT

This command reads the specified input file, sorts the data according to the supplied parameters and writes the results to either the screen, a file or to another output device, like a printer. Sorting can be done in ascending or descending order.

The DOS sort program is rather primitive in its capabilities. Many programs incorporate data sort features which you can use in place of this utility.

See the DOS users manual for details of command syntax and command parameters.


STACKS

This command must be included within the CONFIG.SYS file. It supports dynamic use of data stacks which handle system hardware interrupts - control codes that devices use to gain access to the system. The command parameters allow the user to specify the number of stacks to be used and the size in bytes of each stack.

See the DOS users manual for details of command syntax and command parameters.


SUBMENU

This command must be included within the CONFIG.SYS file. It defines an item to be included on a startup menu which, when selected, calls up another set of choices within the submenu chosen. The command is used to customize multiple configuration command menus.


SUBST

The command is used to alias or substitute a path with a virtual drive through a drive letter. The command can be issued from the keyboard interactively or from within a command file. The drive letter assigned as an alias is a virtual drive. It can be used to substitute for the specified path as if it were a real physical drive. The command cannot be used from within Windows.


SWITCHES

Used only from within the CONFIG.SYS file, this command specifies special command switch options:

Switches:

/F
Skips the 2-second delay after displaying the opening DOS banner message during boot or startup.

/K
Forces an enhanced keyboard to act like a conventional keyboard.

/N
Disables the use of the F5 or F8 keystrokes to bypass startup commands. (SWITCHES /N does not prevent entry of the CTRL+F5 or CTRL+F8 keystroke combinations to bypass DRVSPACE.BIN. This can be prevented by using the DRVSPACE /SWITCHES command to add the SWITCHES /N setting to the DRVSPACE.INI file.)

/W
Specifies that the WINA20.386 file has been moved to a directory other than the root directory. This is a critical system file.


SYS

This command is used to transfer the DOS operating system files to another disk. It copies the critical system files to the new disk or diskette.

FORM and EXAMPLE: SYS A: - transfers the system to drive A:

WARNING: This command can be issued from a commmand prompt on a floppy diskette which has been formatted to be bootable and contains the SYS.COM command file. If this is done it can overwrite the hard disk's operating system files. This can cause irreparable damage to the disk if the operating system versions are not the same.


TIME

This command can be invoked at any system prompt to display or change the system's time setting.


TREE

The TREE command is used to generate a hierarchical listing of all the directories on the specified drive. This is a very useful way to view the entire directory structure of a disk. Below is a partial example of what the display looks like:



TYPE

This command displays the contents of a text file on the screen or on another output device. Output can be piped to a file, as well.

FORM and EXAMPLE: TYPE MYFILE.TXT - displays the specified file on the screen.

The command can be used with the MORE command to paginate output and prompt the user for continued viewing.


UNDELETE

This command can be used to restore files which were previously erased or deleted but only if it is used before the file areas allocated to the erased files have not already been overwritten by data from other, newer files.

See the DOS users manual for details of command syntax and program parameters.


UNFORMAT

This command can be used to restore a disk which has been accidentally formatted. This can only be done if the diskette or disk has not been formatted unconditionally, in which case, critical unformatting information has not been saved. The command can only be used to restore local hard disks or floppy disks. It will not work on networked drives. The command can also be used to refresh or rebuild a corrupted file allocation table on a hard disk drive.

WARNING: This command can destroy all the data on your hard disk if it is used improperly.

See the DOS users manual for details of command syntax and program parameters.


VER

The VER command displays the version of the current operating system.


VERIFY

This command is generally set in the AUTOEXEC.BAT file. It directs the system to verify that all files are written correctly to disk and displays the status of verification for every file written. The command can also be issued at the system prompt. The verify function greatly slows down disk access and should be used judiciously.

VERIFY is set either to ON or to OFF.


VOL

This command displays the volume label information associated with a specified disk drive it if is assigned and available.


VSAFE

This command invokes the VSafe memory resident virus checking program which monitors all file and disk activity for virus transfers. It is generally executed at startup from within the AUTOEXEC.BAT file. The program continuously monitors the system for viruses and displays warning messages when any are detected. It requires about 22K of conventional memory.


XCOPY

This command is stronger than the related COPY command. It copies whole directories, associated subdirectories and all files within them except for hidden and system files to the specified target. This is much simpler and more powerfule than the simple COPY command, but it is also potentially much more dangerous and needs to be used with some caution.

FORM:

XCOPY source target /Y|-Y /A|M /D:date /P /S /E /V /W

WHERE:

source
Specifies the location and names of the files to be copied including the drive and path. Wildcards (*) are allowed but can be dangerous.

target
Specifies the target to which the file will be copied. It should contain a drive letter and directory name. Wildcards (*) are allowed but can be dangerous.

Optional Switches:

/A
Copies only source files that have archive file attributes set.

/D:date
Copies only source files modified on or after a specified date.

/E
Copies directories and all subdirectories, even if they are empty.

/M
Copies source files that have their archive file attributes set and turns them off.

/P
Prompts for confirmation before creating each destination file.

/S
Copies directories and all subdirectories, unless they are empty.

/V
Verifies each file as it is written to the destination file to make sure that the destination files are identical to the source files.

/W
Displays the following message and waits for confirmation before beginning:

Press any key to begin copying file(s)

/Y
Indicates that existing files will be replaced without prompting for confirmation.

/-Y
Prompts for confirmation when replacing existing files.


Multiple Configurations

Most high-end PCs today have enough disk space and power to permit multiple boot configurations. They can even accomodate several operating systems on the same hard disk in different disk partitions. DOS, itself, can be set up with multiple configurations each of which is specifically designed to meet some specific need. Commonly, multiple configurations are used to set up radically different memory parameters often required by multimedia software programs which can conflict with one another for critical system resources. It may be necessary for you to set up a boot configuration for each one. This can become tedious.

All multiple configuration options are stored in the CONFIG.SYS file along with all the parameters necessary to establish a boot menu which gives the user a choice among several configuration options.

For more detailed information about multiple boot configurations see your DOS user manual.


Safe DOS Commands

Here is a list of DOS commands that under almost all circumstances are completely safe to use anywhere, anytime and can't do anything to hurt your computer system or your existing files and directories:

CHDIR (CD) EXIT MORE TREE
CLS FASTHELP PRINT TYPE
DATE FC PROMPT VER
DIR FIND SCANDISK VERIFY
DOSKEY HELP SET VSAFE
ECHO MEM TIME


Dangerous DOS Commands

Here is a list of DOS commands that should be used with caution under some or all circumstances since they can damage or modify your existing files and directories or significantly modify system parameters so that the computer won't work properly any more. Some can produce changes that are either irreversible or are very difficult to recover from without a good system backup:

APPEND DELTREE * ERASE * RENAME *
XCOPY COPY * FDISK RMDIR (RD) *
DBLSPACE FORMAT RESTORE
DEFRAG LABEL SYS
DISKCOPY * MKDIR (MD) * UNDELETE *
EDIT * MOVE * UNFORMAT

* - commands that are dangerous only if used improperly.
- commands that must be used with extreme caution at all times.


Keystrokes and Keystroke Combinations

Some or all of the common keystrokes and keystroke combinations listed in the table below, along with their functions, will work either in DOS, itself, or in programs which are running under the DOS system. Some keystrokes will perform slightly different functions depending on the application that is being run. Some applications will completely reassign keystrokes. If this is the case, the user manual will generally provide a table showing keystroke equivalents and functions. Keystroke combinations are shown in the following manner:

CTRL+ALT+DEL

This means that you must hold down the control key the alternate function key and the delete key in succession and then let go of all the keys to perform the function - in this case - a warm boot (Don't do this now, please!).

Cursor Control Keys
DnArrow Moves the cursor down one line or down one option choice or option box.
UpArrow Moves the cursor up one line or up one option choice or option box.
RtArrow Moves the cursor one character or space right or one option or choice right.
LftArrow Moves the cursor one character or space left or one option or choice left.
Backspace Moves the cursor back (left) one space or character, generally non-destructively.
Home Sends the cursor to the beginning of a line or to the first option or choice.
Ctrl+Home Sends the cursor to the top of a file or the top of a page or to the first option or choice.
End Sends the cursor to the end of a line or to the last option or choice.
Ctrl+End Sends the cursor to the end of a file or the end of a page or to the last option or choice.
PgUp Scrolls information up one page or up one screen.
PgDn Scrolls information down one page or down one screen.
Tab Moves the cursor to the next tab position or moves to the next choice option or option box.

Editing Keys
Backspace Moves the cursor back (left) one space or character, generally non-destructively.
CapsLock Toggles All Caps mode on and off. The CapsLock light is lit when All Caps Mode is set to on.
Ctrl+Z Ends keyboard input and writes an End of File marker. Used in editors and in creating files from the console.
Del Deletes or erases the keystroke to the immediate left of the current cursor position.
If text is highlighted it removes the entire highlighted selection.
Enter Produces a new line in editors. Sends command input to the system.
Ins Toggles typing mode between insert and overstrike. The default is generally insert.
NumLock Toggles the keypad between numeric and code input modes. The NumLock light is lit when the mode is set to on (numeric).
Return Same as enter (above). Often referred to as "carriage return" and abbreviated <CR>
Shift When depressed this key shifts keyboard character input to uppercase mode.
Tab Inserts a tab at the current cursor position. This may be translated into 8 literal spaces, depending on the software being used.

Flow Control Keys
Ctrl+A Used in some applications to stop output and return to a command prompt.
Ctrl+D Used in some applications to stop output and return to a command prompt.
Ctrl+Q Resumes output from a remote computer.
Ctrl+S Suspends output from a remote computer.
ScrollLock Toggles between continuous output and suspended output. The ScrollLock light is lit when output is suspended.

Program Control Keys
Alt+X Used in many applications to exit and return to the DOS system.
Ctrl+Break Interrupts the current operation and returns control to DOS.
Ctrl+C Sends an soft interrupt to a remote system or local process which generally suspends or ends the current operation.
Ctrl+Y Sends a hard interrupt to a remote system which generally ends whatever process is running.
Ctrl+X Used in some applications to exit and in some applications to close files and exit.
Esc Cancels a request or escapes from a command or operation and returns to a DOS prompt.

System Function Keys
Ctrl+Alt+Del Ends all current operations and reboots the computer. This is often referred to as a "warm boot."
Ctrl+Atl+Ins Ends all current operations and reboots the some computers in system setup mode.
F1 In most applications this keystroke calls up a help screen, often context-specific.
F5 ?
CTRL+F5 ?
F8 Can be used during a warm boot to permit the user to step through the system initializations one at a time. This is very useful for diagnostic purposes.
CTRL+F8 ?
F10 In many applications this will stop all processes and return control to DOS.
PrintScrn Used to send data on the screen to a printer or to a clipboard buffer for use in other applications.


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