Tuesday, August 11, 2009

The MS-DOS 7 Internal Commands


( Embedded in the COMMAND.COM kernel )

Every Windows™ 95/98 "Boot" Floppy Disk or Command prompt in a DOS-Window gives you access (through Command.com) to all of the following commands...


Table of Contents (the Commands)

command cd (chdir) chcp cls copy copy con ctty date del (erase) dir exit lock md (mkdir) path (;) prompt rd (rmdir) ren (rename) set time type unlock ver vol

The following commands are rarely used outside of BATCH files:

break call echo for
(%) (%%) goto if (not) (errorlevel) (==) (exist) lfnfor lh (loadhigh) pause rem shift verify

This first command isn't really an "internal" command at all. It describes all the switches that can be used when executing the COMMAND.COM program itself (and secondary copies):


command    COMMAND.COM ------- Starts a new copy of the Windows Command Interpreter.  COMMAND [[drive:]path] [device] [/E:nnnnn] [/L:nnnn] [/U:nnn] [/P] [/MSG]                        [/LOW] [/Y [/[C|K] command]]  [drive:]path   Specifies the directory containing COMMAND.COM.   device        Specifies the device to use for command input and output.   /E:nnnnn      Sets the initial environment size to nnnnn bytes.                 (nnnnn should be between 256 and 32,768).   /L:nnnn       Specifies internal buffers length (requires /P as well).                 (nnnn should be between 128 and 1,024).   /U:nnn        Specifies the input buffer length (requires /P as well).                 (nnn should be between 128 and 255).   /P            Makes the new Command Interpreter permanent (can't exit).   /MSG          Stores all error messages in memory (requires /P as well).   /LOW          Forces COMMAND to keep its resident data in low memory.   /Y            Steps through the batch program specified by /C or /K.   /C command    Executes the specified command and returns.   /K command    Executes the specified command and continues running.  Back to TOC    cd      Change Directory ------- Displays the name of or changes the current directory.  CHDIR [drive:][path] CHDIR[..] CD [drive:][path] CD[..]     ..  Specifies that you want to change to the parent directory (in         other words: Move up one folder in the directory tree). DOS 7,        WHEN using a DOS-window, allows you to use extra dots here! If        you were in C:\WINDOWS\SYSTEM\shellext, you could enter cd...        to go up to C:\WINDOWS or even cd.... to get to the root.  Type CD drive: to display the current directory in the specified drive. Type CD without parameters to display the current drive and directory.  Back to TOC   chcp     Change Code Page ------- Displays or sets the active code page number.  CHCP [nnn]    nnn   Specifies a code page number.  Type CHCP without a parameter to display the active code page number.  Back to TOC    cls     Clear Screen ------- Clears the screen.  CLS  Back to TOC  
copy Copy or Concatenate Files ------- Copies one or more files to another location. COPY [/A | /B] source [/A | /B] [+ source [/A | /B] [+ ...]] [destination [/A | /B]] [/V] [/Y | /-Y] source Specifies the file or files to be copied. /A Indicates an ASCII text file. /B Indicates a binary file. destination Specifies the directory and/or filename for the new file(s). /V Verifies that new files are written correctly. /Y Suppresses prompting to confirm you want to overwrite an existing destination file. /-Y Causes prompting to confirm you want to overwrite an existing destination file. The switch /Y may be preset in the COPYCMD environment variable. This may be overridden with /-Y on the command line To append files, specify a single file for destination, but multiple files for source (using wildcards or file1+file2+file3 format).
Note this special case of the COPY command:
    copy con output.txt      Copy from Console to ...  After you type this command and press ENTER, MS-DOS copies everything you type to the file OUTPUT.TXT. When you are finished typing, press CTRL+Z to indicate that you want to end the file.  The Control-Z character will appear on the screen as " ^Z ".  You can also end a COPY CON command by pressing the F6 key.  Pressing F6 also generates the Control-Z character; a " ^Z " still appears on the screen.  The following example copies information from the keyboard to a printer connected to LPT1:      copy con lpt1   Back to TOC  
ctty Change Termial Type ------- Changes the terminal device used to control your system. CTTY device device The terminal device you want to use, such as COM1. Back to TOC date ------- Displays or sets the date. DATE [date] Type DATE without parameters to display the current date setting and a prompt for a new one. Press ENTER to keep the same date. Back to TOC
del Delete (Erase) Files ------- Deletes one or more files. DEL [drive:][path]filename [/P] ERASE [drive:][path]filename [/P] [drive:][path]filename Specifies the file(s) to delete. Specify multiple files by using wildcards. /P Prompts for confirmation before deleting each file. Note: In most cases the file is NOT actually "erased"; the space it used is simply noted as being available for new files to write over it. If you really want to erase every word of a sensitive file, you should get a 'security program' designed to overwrite all erased files! Back to TOC
dir Directory Listing ------- Displays a list of files and subdirectories in a directory. DIR [drive:][path][filename] [/P] [/W] [/A[[:]attributes]] [/O[[:]sortorder]] [/S] [/B] [/L] [/V] [drive:][path][filename] Specifies drive, directory, and/or files to list. (Could be enhanced file specification or multiple filespecs.) /P Pauses after each screenful of information. /W Uses wide list format. /A Displays files with specified attributes. attributes D Directories R Read-only files H Hidden files A Files ready for archiving S System files - Prefix meaning not /O List by files in sorted order. sortorder N By name (alphabetic) S By size (smallest first) E By extension (alphabetic) D By date & time (earliest first) G Group directories first - Prefix to reverse order A By Last Access Date (earliest first) /S Displays files in specified directory and all subdirectories. /B Uses bare format (no heading information or summary). /L Uses lowercase. /V Verbose mode. Switches may be preset in the DIRCMD environment variable. Override preset switches by prefixing any switch with - (hyphen)--for example, /-W. Back to TOC
exit ------- Quits the COMMAND.COM program (command interpreter). EXIT
If you're in a DOS-Window in Windows, this will close the window! Back to TOC
lock ------- Locks a drive, enabling direct disk access for an application. LOCK [drive:]
Note: If you use this command in a DOS-Window, it will only affect the floppy disk drives; Windows™ 95/98 does not allow you to lock a drive directly while it is operating. If you try lock C: , you'll get the error message: " Locking operation failed." Back to TOC
md Make Directory ------- Creates a directory. MKDIR [drive:]path MD [drive:]path Back to TOC
path ------- Displays or sets a search path for executable files. PATH [[drive:]path[;...]] PATH ; Type PATH (without any parameters) to display the current path. Type PATH ; (PATH space semi-colon) to CLEAR all search-path settings; this means that DOS will only be able search the current directory.
NOTE: When used in a DOS-Window, these commands ONLY apply to that particular DOS-Window! (The PATH will not be changed globally.) See the SET command for a similar effect in DOS-Windows, and also for a utility (W95envar.zip) that will make global changes! Back to TOC
prompt ------- Changes the Windows command prompt. PROMPT [text] text Specifies a new command prompt. Prompt can be made up of normal characters and the following special codes: $Q = (equal sign) $$ $ (dollar sign) $T Current time $D Current date $P Current drive and path $V Windows version number $N Current drive $G > (greater-than sign) $L < (less-than sign) $B | (pipe) $H Backspace (erases previous character) $E Escape code (ASCII code 27) $_ Carriage return and linefeed Type PROMPT without parameters to reset the prompt to the default setting. Back to TOC
rd Remove (Delete) Directory ------- Removes (deletes) a directory. RMDIR [drive:]path RD [drive:]path Back to TOC ren Rename File or Directory ------- Renames a file/directory or files/directories. RENAME [drive:][path][directoryname1 | filename1] [dirname2 | filename2] REN [drive:][path][directoryname1 | filename1] [dirname2 | filename2] Note that you cannot specify a new drive or path for your destination. Back to TOC
set ------- Displays, sets, or removes Windows environment variables. SET [variable=[string]] variable Specifies the environment-variable name. string Specifies a series of characters to assign to the variable. Type SET without parameters to display the current environment variables.
Note: If you use SET in a DOS-Window to add a variable and string, it will only affect commands run in that particular window! Unlinke Win NT (which has a DOS 'Environment' Tab), Windows™ 95/98 normally will not allow you to set global Environment strings while the OS is running: You have to set them in AUTOEXEC.BAT and reboot the system! However, I recently found that Microsoft made a utility for setting Environment strings from a DOS-window with a 'global' effect... this utility is called WINSET.EXE ( it's archived with another util called SHORTCUT.EXE and labeled as W95ENVARS.EXE ). You can download this now as: W95envar.zip. Back to TOC
time ------- Displays or sets the system time. TIME [time] Type TIME with no parameters to display the current time setting and a prompt for a new one. Press ENTER to keep the same time. Back to TOC
type ------- Displays the contents of text files. TYPE [drive:][path]filename
NOTE: If there are more than 25 lines in the file, you'll need to pipe the screen output through the DOS External Command MORE in order to keep all but the last screen from flashing past you! EXAMPLE: C:\>type tips.txt |more Back to TOC
unlock ------- Unlocks a drive, disabling direct disk access for an application. UNLOCK [drive:]
See LOCK Back to TOC ver Version ------- Displays the Windows version. VER Back to TOC vol Volume Label/SN ------- Displays the disk volume label and serial number, if they exist. VOL [drive:] Note: The DOS command to change a Volume Label is an "External Command" (the program is: LABEL.EXE).
Back to TOC
The following commands are rarely used outside of a BATCH file (such as AUTOEXEC.BAT):
   break ------- Sets or clears extended CTRL+C checking.  BREAK [ON | OFF]  Type BREAK without a parameter to display the current BREAK setting.  Back to TOC   call ------- Calls one batch program from another.  CALL [drive:][path]filename [batch-parameters]    batch-parameters   Specifies any command-line information required by                       the batch program.  Back to TOC   echo ------- Displays messages, or turns command-echoing on or off.    ECHO [ON | OFF]   ECHO [message]  Type ECHO without parameters to display the current echo setting.  Back to TOC    for ------- Runs a specified command for each file in a set of files.  FOR %variable IN (set) DO command [command-parameters]    %variable  Specifies a replaceable parameter.   (set)      Specifies a set of one or more files.  Wildcards may be used.   command    Specifies the command to carry out for each file.   command-parameters              Specifies parameters or switches for the specified command.  To use the FOR command in a batch program, specify %%variable instead of %variable.  Back to TOC   goto ------- Directs Windows to a labelled line in a batch program.  GOTO label    label   Specifies a text string used in the batch program as a label.  You type a label on a line by itself, beginning with a colon.  Example:  The following batch program formats a disk in drive A as a system disk. If the operation is successful, the GOTO command simply directs MS-DOS to the label named "end"; if not, an error message is displayed:      echo off     format a: /s     if not errorlevel 1 goto end     echo An error occurred during formatting.     :end     echo Successfully formatted the disk in drive A.   Back to TOC    if ------- Performs conditional processing in batch programs.  IF [NOT] ERRORLEVEL number command IF [NOT] string1==string2 command IF [NOT] EXIST filename command   NOT               Specifies that Windows should carry out the command only                    if the condition is false.  ERRORLEVEL number Specifies a true condition if the last program run                     returned an exit code equal to or greater than the                     number specified.  command           Specifies the command to carry out if the condition is                    met.  string1==string2  Specifies a true condition if the specified text strings                    match.  EXIST filename    Specifies a true condition if the specified filename                    exists.   Note: Although you can only check directly for the existence of a file, you can  also check for directories (folders) by using the NUL operator as a filename.  Example:              if exist C:\TEMP\NUL goto done     will route program flow to   the label "done" only if the folder C:\TEMP exists!    Back to TOC   lfnfor   Long File Name FOR ------- Enables/Disables Long file names when processing FOR commands.  LFNFOR [ON | OFF]  Type LFNFOR without a parameter to display the current setting.  Back to TOC    lh      Load High ------- Loads a program into the upper memory area.  LH [drive:][path]filename [parameters] LOADHIGH [drive:][path]filename [parameters] LOADHIGH [/L:region1[,minsize1][;region2[,minsize2]...] [/S]]          [drive:][path]filename [parameters]  /L:region1[,minsize1][;region2[,minsize2]]...             Specifies the region(s) of memory into which to load             the program.  Region1 specifies the number of the first             memory region; minsize1 specifies the minimum size, if             any, for region1.  Region2 and minsize2 specify the             number and minimum size of the second region, if any.             You can specify as many regions as you want.  /S          Shrinks a UMB to its minimum size while the program             is loading.  [drive:][path]filename             Specifies the location and name of the program.  Back to TOC   pause ------- Suspends processing of a batch program and displays the message: Press any key to continue....  PAUSE  Back to TOC   rem ------- Records comments (remarks) in a batch file or CONFIG.SYS.  REM [comment]  Back to TOC   shift ------- Changes the position of replaceable parameters in a batch file.  SHIFT  Back to TOC   verify ------- Tells Windows whether to verify that your files are written correctly to a disk.  VERIFY [ON | OFF]  Type VERIFY without a parameter to display the current VERIFY setting.  Back to TOC 

MS-DOS 7 Contents Page.

How To Make a Boot Disk.

"The Starman's Realm" INDEX Page .

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