1.\" Copyright (c) 1980, 1991, 1993 2.\" The Regents of the University of California. All rights reserved. 3.\" 4.\" Redistribution and use in source and binary forms, with or without 5.\" modification, are permitted provided that the following conditions 6.\" are met: 7.\" 1. Redistributions of source code must retain the above copyright 8.\" notice, this list of conditions and the following disclaimer. 9.\" 2. Redistributions in binary form must reproduce the above copyright 10.\" notice, this list of conditions and the following disclaimer in the 11.\" documentation and/or other materials provided with the distribution. 12.\" 3. All advertising materials mentioning features or use of this software 13.\" must display the following acknowledgement: 14.\" This product includes software developed by the University of 15.\" California, Berkeley and its contributors. 16.\" 4. Neither the name of the University nor the names of its contributors 17.\" may be used to endorse or promote products derived from this software 18.\" without specific prior written permission. 19.\" 20.\" THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND 21.\" ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 22.\" IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 23.\" ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE 24.\" FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 25.\" DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 26.\" OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 27.\" HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 28.\" LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 29.\" OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 30.\" SUCH DAMAGE. 31.\" 32.\" @(#)sticky.8 8.1 (Berkeley) 6/5/93 33.\" $FreeBSD$ 34.\" 35.Dd June 5, 1993 36.Dt STICKY 7 37.Os 38.Sh NAME 39.Nm sticky 40.Nd sticky text and append-only directories 41.Sh DESCRIPTION 42A special file mode, called the 43.Em sticky bit 44(mode S_ISTXT), 45is used to indicate special treatment 46for directories. 47It is ignored for regular files. 48See 49.Xr chmod 2 50or 51the file 52.In sys/stat.h 53for an explanation of file modes. 54.Sh STICKY DIRECTORIES 55A directory whose `sticky bit' is set 56becomes an append-only directory, or, more accurately, 57a directory in which the deletion of files is restricted. 58A file in a sticky directory may only be removed or renamed 59by a user if the user has write permission for the directory and 60the user is the owner of the file, the owner of the directory, 61or the super-user. 62This feature is usefully applied to directories such as 63.Pa /tmp 64which must be publicly writable but 65should deny users the license to arbitrarily 66delete or rename each others' files. 67.Pp 68Any user may create a sticky directory. 69See 70.Xr chmod 1 71for details about modifying file modes. 72.Sh HISTORY 73A 74.Nm 75command appeared in 76.At 32v . 77.Sh BUGS 78Neither 79.Xr open 2 80nor 81.Xr mkdir 2 82will create a file with the sticky bit set. 83