xref: /freebsd/share/man/man7/sticky.7 (revision 640235e2c2ba32947f7c59d168437ffa1280f1e6)
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28.\"     @(#)sticky.8	8.1 (Berkeley) 6/5/93
29.\" $FreeBSD$
30.\"
31.Dd June 5, 1993
32.Dt STICKY 7
33.Os
34.Sh NAME
35.Nm sticky
36.Nd sticky text and append-only directories
37.Sh DESCRIPTION
38A special file mode, called the
39.Em sticky bit
40(mode S_ISTXT),
41is used to indicate special treatment
42for directories.
43It is ignored for regular files.
44See
45.Xr chmod 2
46or
47the file
48.In sys/stat.h
49for an explanation of file modes.
50.Sh STICKY DIRECTORIES
51A directory whose `sticky bit' is set
52becomes an append-only directory, or, more accurately,
53a directory in which the deletion of files is restricted.
54A file in a sticky directory may only be removed or renamed
55by a user if the user has write permission for the directory and
56the user is the owner of the file, the owner of the directory,
57or the super-user.
58This feature is usefully applied to directories such as
59.Pa /tmp
60which must be publicly writable but
61should deny users the license to arbitrarily
62delete or rename each others' files.
63.Pp
64Any user may create a sticky directory.
65See
66.Xr chmod 1
67for details about modifying file modes.
68.Sh HISTORY
69A
70.Nm
71command appeared in
72.At 32v .
73.Sh BUGS
74Neither
75.Xr open 2
76nor
77.Xr mkdir 2
78will create a file with the sticky bit set.
79