Testing If a Drive or Directory Exists from a Batch File (65994)


The information in this article applies to:
    • Microsoft MS-DOS operating system 3.1
    • Microsoft MS-DOS operating system 3.2
    • Microsoft MS-DOS operating system 3.21
    • Microsoft MS-DOS operating system 3.3
    • Microsoft MS-DOS operating system 3.3a
    • Microsoft MS-DOS operating system 4.0
    • Microsoft MS-DOS operating system 4.01
    • Microsoft MS-DOS operating system 5.0
    • Microsoft MS-DOS operating system 5.0a
    • Microsoft MS-DOS operating system 6.0
    • Microsoft MS-DOS operating system 6.2
    • Microsoft MS-DOS operating system 6.21
    • Microsoft MS-DOS operating system 6.22
    • Microsoft Windows for Workgroups 3.11
This article was previously published under Q65994

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
Modification Type: Major Last Reviewed: 5/12/2003
Keywords: KB65994 kbAudDeveloper
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