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: src/share/man/man8/sticky.8,v 1.7.2.1 2001/08/17 13:08:50 ru Exp $ 30.\" $DragonFly: src/share/man/man8/sticky.8,v 1.5 2006/05/26 19:39:40 swildner Exp $ 31.\" 32.Dd June 5, 1993 33.Dt STICKY 8 34.Os 35.Sh NAME 36.Nm sticky 37.Nd sticky text and append-only directories 38.Sh DESCRIPTION 39A special file mode, called the 40.Em sticky bit 41(mode S_ISVTX), 42is used to indicate special treatment 43for directories. 44It is ignored for regular files. 45See 46.Xr chmod 2 47or 48the file 49.In sys/stat.h 50for an explanation of file modes. 51.Sh STICKY DIRECTORIES 52A directory whose `sticky bit' is set 53becomes an append-only directory, or, more accurately, 54a directory in which the deletion of files is restricted. 55A file in a sticky directory may only be removed or renamed 56by a user if the user has write permission for the directory and 57the user is the owner of the file, the owner of the directory, 58or the super-user. 59This feature is usefully applied to directories such as 60.Pa /tmp 61which must be publicly writable but 62should deny users the license to arbitrarily 63delete or rename each others' files. 64.Pp 65Any user may create a sticky directory. 66See 67.Xr chmod 1 68for details about modifying file modes. 69.Sh HISTORY 70A 71.Nm 72command appeared in 73.At 32v . 74.Sh BUGS 75Neither 76.Xr open 2 77nor 78.Xr mkdir 2 79will create a file with the sticky bit set, it must 80be chmod'd after the fact. 81However, 82.Xr mkdir 1 83will do the right thing. 84