                            SUBST

The SUBST external command lets you substitute (refer to, use) a disk drive 
letter instead of a long pathname for a frequently used directory. SUBST is the
opposite of JOIN. ASSIGN can also be used to substitute one disk drive letter 
for another.

    SUBST  d1: [d2:][pathname]
      or
    SUBST  d1: /D
      or
    SUBST

d1: is the substitute drive letter you are defining. d1: must be within the 
    range of valid letters established by the LASTDRIVE line in your 
    CONFIG.SYS file.

[d2:][pathname] is an existing pathname on a disk drive other than d1: that 
    d1: is defining a substitute for. 

/D deletes a previously defined substitute.

SUBST with no options will display a list of the currently defined substitute 
drives. SUBST won't work for disks on another computer in a network. Trying
to use ASSIGN, BACKUP, CHKDSK, DISKCOMP, DISKCOPY, FDISK, FORMAT, JOIN, LABEL, 
REPLACE, or RESTORE on a disk defined by SUBST should be avoided.
