DOS Internal Commands

The DOS (Windows 9x) internal commands are so-called because their instructions are a part of COMMAND.COM, the DOS (Windows 9x) command line interpreter.

Recall that COMMAND.COM is placed into memory each time the DOS or Windows 9x OS is booted. Thefore, the internal commands are always in memory and can always be executed from any command line prompt.

This is in contrast to the disk-bound external commands, which reside in secondary memory up until the moment they are needed, at which time the OS must find them and load them into primary memory.

The syntax for some frequently used internal commands follows.

   TIME
   Displays current time and allows it to be changed.
   Syntax: TIME

   DATE
   Displays current date and allows it to be changed.
   Syntax: DATE

   CLS
   Clears the screen.
   Syntax: CLS

   DIR
   Shows directory information of a diskette: name, size, and the
   date and time stamp of files.

   Syntax: DIR  [d:][path]
    Optional switches:
    /p  Display dir info and pauses display when the screen is full
    /w  Display names and extensions only in five columns

    To display a file directory listing for D:\LET\ANNUAL
        D:\LET\ANNUAL>DIR                  (from D:\LET\ANNUAL)
        D:\DATA>DIR  \LET\ANNUAL           (from D:\DATA)
        C:\WINDOWS>DIR  D:\LET\ANNUAL      (from C:\WINDOWS)

   
   COPY
   Copies a file. Name of copy may be the same as original, or different.
   Syntax: COPY [d:][path][name.ext]  [d:][path][name.ext]
    Optional switches:
    /v  Verify, copies the file and compares it with the original
    /b  Binary file

    To copy a file from D:\BATCH to the root of A: drive
        A:\>COPY  D:\BATCH\CL.BAT                (from A: drive)
        D:\BATCH>COPY  CL.BAT  A:\               (from D:\BATCH)

    To copy a file from the root of C: to A: drive and change its name
        A:\>COPY  C:\MSDOS.SYS  MSDOSSYS.BAK     (from A:)
        C:\>COPY  MSDOS.SYS  A:\MSDOSSYS.BAK     (from the root of C:)

    To copy all of the files from the root of A: to D:\CCV\ENGCOMP
        A:\>COPY  *.*  D:\CCV\ENGCOMP            (from A:)
        D:\CCV\ENGCOMP>COPY  *.*  A:\            (from D:\CCV\ENGCOMP)

   TYPE
   Displays the contents of a file.
   Syntax: TYPE [d:][path][name.ext]
   To display the contents of the file MY.LET to the screen
        A:\>TYPE  MY.LET
   DEL
   Deletes a file from disk.
   Syntax: DEL [d:][path][name.ext]
    To delete one file:
        A:\>DEL  A:\MY.LET 
    To del all files in current directory
        A:\>DEL  *.*
   REN
   Renames a file.
   Syntax: REN [d:][path][name.ext] [d:][path][newname.ext] 
    To change the name of the file D:\LET\ANNUAL\99.DOC to 1999.DOC
        D:\LET>REN  ANNUAL\99.DOC  1999.DOC             (from D:\LET)
        D:\DATA>REN  \LET\ANNUAL\99.DOC  1999.DOC       (from D:\DATA)
        C:\WINDOWS>REN  D:\LET\ANNUAL\99.DOC  1999.DOC  (from C:\WINDOWS)

   MD
   Makes (creates) a new directory.
   Syntax: MD [d:][path][dirname]
    To create a directory named HERMIT in the root of D: drive
        D:\>MD HERMIT                       (from D:\)
        C:\>MD D:\HERMIT                    (from C:\)
   RD
   Removes an existing directory            (directory must be empty). 
   Syntax: RD [d:][path][dirname]
    To remove the HERMIT sub-directory
        D:\>RD HERMIT                       (from D:\)
        C:\>RD D:\HERMIT                    (from C:\)
   CD
   Changes the current directory.
   Syntax: CD [path][dirname]
    To make D:\HERMIT the current directory
        D:\>CD  HERMIT                      (from D:\)
        D:\DATA>CD  \HERMIT                 (from D:\DATA)
        D:\DATA\SOURCE>CD \HERMIT           (from D:\DATA\SOURCE)
        D:\DATA\SOURCE>CD ..                (from D:\DATA\SOURCE)
   
   PATH
   The PATH command is used to help the command interpreter find 
   external commands which are not in the current directory. The 
   command interpretter looks into the 
DOS environment for "PATH=" and then searches the 
   paths (each separated from the next by a semicolon) that follow. 
   Syntax:  PATH=[path;path;...] 
    To set the DOS PATH:
        PATH=C:\DOS;C:\PCW;\C:\BIN
    To display the current path:
        PATH

   SET PROMPT
   Used to specify the appearance of the DOS prompt.
   Syntax:  SET PROMPT=        (from the command line)
            PROMPT=            (in a batch file)
    To display current drive & current path followed by ">" as prompt
        SET PROMPT=$P$G
    To display the current date, time, and drive on separate lines
        SET PROMPT $D$_$T$_$N$G
    To redefine F9 to CD\Windows\Start Menu\Programs\Startup
        SET PROMPT $e[0,67;"'CD\Windows\Start Menu\Programs\Startup'";13p