Type: External (3.1 and later)
SUBST d: d:path
SUBST d: /D
Purpose: Substitutes a virtual drive letter for a path designation.
Use the SUBST command to substitute a drive letter for a path in order to treat a virtual drive (a reserved area rather than an actual disk drive) as a physical drive. In order to enter drive designations using any letter (other than just the letters for the physical drives installed in your computer), you may have to add this line to a CONFIG.SYS file that should be placed in the root directory of your startup drive: LASTDRIVE=Z Six DOS commands cannot be used with virtual drives created with the SUBST command. They are: CHKDSK DISKCOPY FDISK FORMAT LABEL SYS If you enter the SUBST command without options , the program will display the name of the current virtual drives that are in effect (if any). For more information on using the SUBST command and other fixed-disk commands, refer to Chapter 3, Using Fixed Disks.
To create a virtual drive F for the path, NEW\DRIVE (under the root directory) of drive C, enter subst f: c:\new\drive
Read and write requests to either drive F or to C:\NEW\DRIVE will be stored in the C:\NEW\DRIVE directory area.