SUBST

By | 2007-04-25

Substitute a drive letter for a network or local path.  This comes in handy when you want to reference a directory which may have a really long path by a drive letter.

For example, instead of using 

c:\TopLevelFolder\NextLevelFolder\ThirdLevelFolder\AlmostThere\FinallyAtMyDestination

you could reference it by a drive letter, say, X:.  To do this, just use the command:

SUBS X: c:\TopLevelFolder\NextLevelFolder\ThirdLevelFolder\AlmostThere\FinallyAtMyDestination\

I’ve included the help file below for SUBST.  Hope this helps someone out there!

Syntax

SUBST drive_letter: path

SUBST 

SUBST drive_letter: /D

Key

SUBST with no parameters will display current SUBST drives

/D : Delete the drive_letter substitution.Compared to mapping a drive with NET USE the SUBST command allows mapping to a subfolder of a drive share – for the storage of user profiles this reduces the number of shares you need to create on the server.

Bugs

Under NT 4 SUBST”ed drives cannot be disconnected using the Explorer GUI – this was fixed in Windows 2000.

In Windows 2000 (and above) you will have problems creating, accessing and deleting drive mappings with SUBST. 

However under Win 2K/XP the functionality of the NET USE command is improved so you can now do 
NET USE g: \\server\share\folder1\folder2

If the network resource is unavailable (ie the server is down) SUBST will continually retry – unlike NET USE which will try to connect once and fail – depending on your application this may be a good or a bad thing – a subst drive that is not available will badly impact performance of most applications.

Notice that when SUBST is used against a local shared folder, it will create a RECYCLER for that drive. The RECYCLER is not removed when the drive substitution is removed, but can be deleted manually.

Author: dwirch

Derek Wirch is a seasoned IT professional with an impressive career dating back to 1986. He brings a wealth of knowledge and hands-on experience that is invaluable to those embarking on their journey in the tech industry.

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