Microsoft KB Archive/65994

= Testing If a Drive or Directory Exists from a Batch File =

Article ID: 65994

Article Last Modified on 11/16/2006

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APPLIES TO


 * Microsoft MS-DOS 3.1
 * Microsoft MS-DOS 3.2 Standard Edition
 * Microsoft MS-DOS 3.21 Standard Edition
 * Microsoft MS-DOS 3.3 Standard Edition
 * Microsoft MS-DOS 3.3a
 * Microsoft MS-DOS 4.0 Standard Edition
 * Microsoft MS-DOS 4.01 Standard Edition
 * Microsoft MS-DOS 5.0 Standard Edition
 * Microsoft MS-DOS 5.0a
 * Microsoft MS-DOS 6.0 Standard Edition
 * Microsoft MS-DOS 6.2 Standard Edition
 * Microsoft MS-DOS 6.21 Standard Edition
 * Microsoft MS-DOS 6.22 Standard Edition
 * Microsoft Windows for Workgroups 3.11

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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

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

Keywords: KB65994

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