ATTRIB
ATTRIB is a command, in DOS, OS/2 and Microsoft Windows that allows the user to change various characteristics, or "attributes" of a file or directory.
Background
Several Microsoft operating systems provided a set of modifiable file characteristics that could be accessed and changed through a low-level system call. For example, as of release 4.0, the first six bits of the file attribute byte indicated whether or not a file was read-only (as opposed to writeable), hidden, a system file, a volume label, a subdirectory, or if the file had been "archived" (with the bit being set if the file had changed since the last use of the BACKUP command).[1] However, initial releases of the operating system did not provide user-level method for reading or changing these values.[2]
History
The initial version of the ATTRIB command was first included in version 3.0 of PC-DOS, with functionality limited to changing the read-only attribute.[2] Subsequent versions allowed the read-only, hidden, system and archive bits to be set.[3] MS-DOS version 3.3 added the capability of recursive searching through subdirectories to display attributes of specified files.[4]
Uses
Setting the read-only bit of a file provided only partial protection against inadvertent deletion: while commands such as del and erase would respect the attribute, other commands such as DELTREE did not.[5] Changing the system attribute was not possible in early versions of Windows, thus requiring use of ATTRIB.[5] Similarly, a system crash in early versions of Windows could lead to a situation where a temporary file had the read-only bit set and was additionally (and irrevocably) locked by the Windows OS; in this instance, booting into DOS (thus avoiding the Windows lock) and unsetting the read-only attribute with ATTRIB was the recommended way of deleting the file.[6] Manipulating the archive bit allowed users to control which files were backed up using the BACKUP command.[2]
See also
chattr, the equivalent on Unix and Linuxcacls, the Windows NT access control list (ACL) utility- List of DOS commands
References
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