Associates a path with a drive letter.
SUBST [drive1: [drive2:]path]
SUBST drive1: /D
drive1: Specifies a virtual drive to which you want to assign a path.
[drive2:]path Specifies a physical drive and path you want to assign to
a virtual drive.
/D Deletes a substituted (virtual) drive.
SUBST d: C:\myPathThatWill\Become\ARootDrive
Restart the process that must see this new virtual drive otherwise the application may not found the path. The application may capture the drive state when starting.
Type SUBST with no parameters to display a list of current virtual drives.
SUBST
D:\: => E:\d
SUBST drive1: /D