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