DOCUMENT:Q65994  17-DEC-2000  [msdos]
TITLE   :Testing If a Drive or Directory Exists from a Batch File
PRODUCT :Microsoft Disk Operating System
PROD/VER:MS-DOS:3.x,4.x,5.x,6.0,6.2,6.21,6.22; WINDOWS:3.11
OPER/SYS:
KEYWORDS:

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The information in this article applies to:

 - Microsoft MS-DOS operating system versions 3.1, 3.2, 3.21, 3.3, 3.3a, 4.0, 4.01, 5.0, 5.0a, 6.0, 6.2, 6.21, 6.22 
 - Microsoft Windows for Workgroups version 3.11 
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SUMMARY
=======

You can use the IF EXIST statement to check for the presence of a directory. For
example, to test for C:\WIN and then change to C:\WIN if it exists, use the
following batch file:

   C:
   IF NOT EXIST C:\WIN\NUL GOTO NOWINDIR
   CD \WIN
   :NOWINDIR

MORE INFORMATION
================

NUL always exists on a local MS-DOS FAT drive; therefore, if C:\WIN exists,
C:\WIN\NUL exists. This technique can also be used to verify that a drive
exists. For example:

   IF EXIST E:\NUL GOTO USE_E

If an unformatted disk is tested, or if the floppy disk drive is empty, an INT 24
error (Abort, Retry, Fail?) occurs.

Neither of these tests works correctly with network devices or any other device
that does not have a block device-driver-controlled FAT file system (for
example, when you are using Windows for Workgroups 3.11 with 32-Bit File Access
enabled).

Prior to using this technique, you should know what network software the client
is using, what type of server they're connecting to, and the file system the
server is using.

The following table shows when IF EXIST returns NUL:

                                                         With 32-Bit File
                             No 32-Bit    With 32-Bit   Access and NetWare

Drive Type                  File Access   File Access    3.x connectivity

Local FAT                    correctly      always            never
Windows for Workgroups FAT   correctly      always            never
Microsoft LAN Manager HPFS     never        always            never
Windows NT FAT/NTFS            never        always            never
NetWare                      correctly      never             never

Additional query words: 3.20 3.21 3.30 3.30a 4.00 4.01 5.00 5.00a 6.00 6.20 6.21 6.22 vfat lanman true false positive negative

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Keywords          :  
Technology        : kbAudDeveloper kbWFWSearch kbWFW311 kbMSDOSSearch kbMSDOS321 kbMSDOS400 kbMSDOS320 kbMSDOS330a kbMSDOS621 kbMSDOS622 kbMSDOS620 kbMSDOS600 kbMSDOS310 kbMSDOS500 kbMSDOS330 kbMSDOS401 kbMSDOS500a
Version           : MS-DOS:3.x,4.x,5.x,6.0,6.2,6.21,6.22; WINDOWS:3.11

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