------------------------- MS-DOS v6.22 Help: SUBST -------------------------
<Notes> <Examples>                                               <Index>


Associates a path with a drive letter.

The drive letter you assign represents a virtual drive, because you can use
the drive letter in commands as if it were a physical drive.

Do not use the SUBST command when Windows is running.


    SUBST [drive1: [drive2:]path]

    SUBST drive1: /D

To display the names of the virtual drives in effect, use the following



    Specifies the virtual drive to which you want to assign a path.

    Specifies the physical drive that contains the specified path (if
    different from the current drive).

    Specifies the path that you want to assign to a virtual drive.


    Deletes a virtual drive.

Related Command

For information about increasing the number of available drive letters, see
the <LASTDRIVE> command.


<Syntax> <Examples>


Using other commands with SUBST

The following commands do not work, or should not be used, on drives used in
the SUBST command:

ASSIGN           DISKCOPY          RECOVER
BACKUP           FDISK             RESTORE
CHKDSK           FORMAT            SYS
DEFRAG           LABEL             UNDELETE /S

Valid drive1 values

The drive1 parameter must be within the range specified by the LASTDRIVE
command. If not, SUBST displays the following error message:

    Invalid parameter - drive1:

Using SUBST with Microsoft Windows

Do not create or delete virtual drives using the SUBST command while
Microsoft Windows is running. If you want to create or delete a virtual
drive using the SUBST command, quit Windows, create or delete the virtual
drive, and then start Windows again.

Using SUBST with compressed drives

You can use SUBST to associate a path on a compressed drive with a drive
letter. However, the drive size and free space of the SUBST drive (for
example, as reported by the DIR command) might not match the drive size and
free space reported for the compressed drive.


<Syntax> <Notes>


The following command creates a virtual drive Z for the path

    subst z: b:\user\betty\forms

Now, instead of typing the full path, you can reach this directory by typing
the letter of the virtual drive, followed by a colon, as in the following


This example works only if you have included the line LASTDRIVE=Z in your
CONFIG.SYS file to define Z as the highest letter that MS-DOS recognizes as
a disk drive. For more information, see the <LASTDRIVE> command.


<Top of page>
Last update: December 07, 2002 14:45 by
Content © 1997 Microsoft Corporation
All else © 2000-2005