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. Neither the name of the University nor the names of its contributors 13.\" may be used to endorse or promote products derived from this software 14.\" without specific prior written permission. 15.\" 16.\" THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND 17.\" ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 18.\" IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 19.\" ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE 20.\" FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 21.\" DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 22.\" OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 23.\" HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 24.\" LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 25.\" OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 26.\" SUCH DAMAGE. 27.\" 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