STICKY(8)

NAME
sticky - sticky text and append-only directories

DESCRIPTION
A special file mode, called the sticky bit (mode S_ISVTX), is used to indicate special treatment for shareable executable files and directories. See chmod(2) or the file /usr/include/sys/stat.h for an explanation of file modes.

STICKY TEXT EXECUTABLE FILES
The sticky bit has no effect on executable files. All optimization on whether text images remain resident in memory is handled by the kernel's virtual memory system.

STICKY DIRECTORIES
A directory whose `sticky bit' is set becomes an append-only directory, or, more accurately, a directory in which the deletion of files is restricted. A file in a sticky directory may only be removed or renamed by a user if the user has write permission for the directory and the user is the owner of the file, the owner of the directory, or the super-user. This feature is usefully applied to directories such as /tmp which must be publicly writable but should deny users the license to arbitrarily delete or rename each others' files.

Any user may create a sticky directory. See chmod(1) for details about modifying file modes.

BUGS
Neither open(2) nor mkdir(2) will create a file with the sticky bit set.

HISTORY
A sticky command appeared in Version 32V AT&T UNIX.