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.\"     @(#)sticky.8	8.1 (Berkeley) 6/5/93
.\" $FreeBSD: src/share/man/man8/sticky.8,v 1.7.2.1 2001/08/17 13:08:50 ru Exp $
.\" $DragonFly: src/share/man/man8/sticky.8,v 1.4 2006/02/17 19:37:10 swildner Exp $
.\"
.Dd June 5, 1993
.Dt STICKY 8
.Os
.Sh NAME
.Nm sticky
.Nd sticky text and append-only directories
.Sh DESCRIPTION
A special file mode, called the
.Em sticky bit
(mode S_ISVTX),
is used to indicate special treatment
for directories.
It is ignored for regular files.
See
.Xr chmod 2
or
the file
.Pa /usr/include/sys/stat.h
for an explanation of file modes.
.Sh 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
.Pa /tmp
which must be publicly writable but
should deny users the license to arbitrarily
delete or rename each others' files.
.Pp
Any user may create a sticky directory.
See
.Xr chmod 1
for details about modifying file modes.
.Sh HISTORY
A
.Nm
command appeared in
.At 32v .
.Sh BUGS
Neither
.Xr open 2
nor
.Xr mkdir 2
will create a file with the sticky bit set, it must
be chmod'd after the fact.
However,
.Xr mkdir 1
will do the right thing.