MS DOS Command: SUBST.EXE

Reference from Microsoft MS-DOS cmd help

Description

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.

Syntax

SUBST [drive1: [drive2:]path] SUBST drive1: /D

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

SUBST

Parameters

drive1:	Specifies the virtual drive to which you want to assign a path.
drive2:	Specifies the physical drive that contains the specified path (if different from the current drive).
path	Specifies the path that you want to assign to a virtual drive.

Switch

/D	Deletes a virtual drive.

Related Command

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

Remarks

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
DISKCOMP	MIRROR

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.

Examples

The following command creates a virtual drive Z for the path B:\USER\BETTY\FORMS:

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 example:

z:

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.