1.\" $NetBSD: chmod.1,v 1.21 2005/12/09 20:27:02 wiz Exp $ 2.\" 3.\" Copyright (c) 1989, 1990, 1993, 1994 4.\" The Regents of the University of California. All rights reserved. 5.\" 6.\" This code is derived from software contributed to Berkeley by 7.\" the Institute of Electrical and Electronics Engineers, Inc. 8.\" 9.\" Redistribution and use in source and binary forms, with or without 10.\" modification, are permitted provided that the following conditions 11.\" are met: 12.\" 1. Redistributions of source code must retain the above copyright 13.\" notice, this list of conditions and the following disclaimer. 14.\" 2. Redistributions in binary form must reproduce the above copyright 15.\" notice, this list of conditions and the following disclaimer in the 16.\" documentation and/or other materials provided with the distribution. 17.\" 3. Neither the name of the University nor the names of its contributors 18.\" may be used to endorse or promote products derived from this software 19.\" without specific prior written permission. 20.\" 21.\" THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND 22.\" ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 23.\" IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 24.\" ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE 25.\" FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 26.\" DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 27.\" OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 28.\" HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 29.\" LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 30.\" OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 31.\" SUCH DAMAGE. 32.\" 33.\" @(#)chmod.1 8.4 (Berkeley) 3/31/94 34.\" 35.Dd December 9, 2005 36.Dt CHMOD 1 37.Os 38.Sh NAME 39.Nm chmod 40.Nd change file modes 41.Sh SYNOPSIS 42.Nm 43.Oo 44.Fl R 45.Op Fl H | Fl L | Fl P 46.Oc 47.Op Fl h 48.Ar mode 49.Ar 50.Sh DESCRIPTION 51The 52.Nm 53utility modifies the file mode bits of the listed files 54as specified by the 55.Ar mode 56operand. 57.Pp 58The options are as follows: 59.Bl -tag -width Ds 60.It Fl H 61If the 62.Fl R 63option is specified, symbolic links on the command line are followed. 64(Symbolic links encountered in the tree traversal are not followed.) 65.It Fl L 66If the 67.Fl R 68option is specified, all symbolic links are followed. 69.It Fl P 70If the 71.Fl R 72option is specified, no symbolic links are followed. 73.It Fl R 74Change the modes of the file hierarchies rooted in the files 75instead of just the files themselves. 76.It Fl h 77If 78.Ar file 79is symbolic link, the mode of the link is changed. 80.El 81.Pp 82The 83.Fl H , 84.Fl L 85and 86.Fl P 87options are ignored unless the 88.Fl R 89option is specified. 90In addition, these options override each other and the 91command's actions are determined by the last one specified. 92.Pp 93Only the owner of a file or the super-user is permitted to change 94the mode of a file. 95.Sh EXIT STATUS 96The 97.Nm 98utility exits 0 on success, and \*[Gt]0 if an error occurs. 99.Sh MODES 100Modes may be absolute or symbolic. 101An absolute mode is an octal number constructed by 102.Em or Ap ing 103the following values: 104.Pp 105.Bl -tag -width 6n -compact -offset indent 106.It Li 4000 107set-user-ID-on-execution 108.It Li 2000 109set-group-ID-on-execution 110.It Li 1000 111sticky bit, see 112.Xr chmod 2 113.It Li 0400 114read by owner 115.It Li 0200 116write by owner 117.It Li 0100 118execute (or search for directories) by owner 119.It Li 0070 120read, write, execute/search by group 121.It Li 0007 122read, write, execute/search by others 123.El 124.Pp 125The read, write, and execute/search values for group and others 126are encoded as described for owner. 127.Pp 128The symbolic mode is described by the following grammar: 129.Bd -literal -offset indent 130mode ::= clause [, clause ...] 131clause ::= [who ...] [action ...] last_action 132action ::= op [perm ...] 133last_action ::= op [perm ...] 134who ::= a | u | g | o 135op ::= + | \- | = 136perm ::= r | s | t | w | x | X | u | g | o 137.Ed 138.Pp 139The 140.Ar who 141symbols ``u'', ``g'', and ``o'' specify the user, group, and other parts 142of the mode bits, respectively. 143The 144.Ar who 145symbol ``a'' is equivalent to ``ugo''. 146.Pp 147.ne 1i 148The 149.Ar perm 150symbols represent the portions of the mode bits as follows: 151.Pp 152.Bl -tag -width Ds -compact -offset indent 153.It r 154The read bits. 155.It s 156The set-user-ID-on-execution and set-group-ID-on-execution bits. 157.It t 158The sticky bit. 159.It w 160The write bits. 161.It x 162The execute/search bits. 163.It X 164The execute/search bits if the file is a directory or any of the 165execute/search bits are set in the original (unmodified) mode. 166Operations with the 167.Ar perm 168symbol ``X'' are only meaningful in conjunction with the 169.Ar op 170symbol ``+'', and are ignored in all other cases. 171.It u 172The user permission bits in the mode of the original file. 173.It g 174The group permission bits in the mode of the original file. 175.It o 176The other permission bits in the mode of the original file. 177.El 178.Pp 179The 180.Ar op 181symbols represent the operation performed, as follows: 182.Bl -tag -width 4n 183.It + 184If no value is supplied for 185.Ar perm , 186the ``+'' operation has no effect. 187If no value is supplied for 188.Ar who , 189each permission bit specified in 190.Ar perm , 191for which the corresponding bit in the file mode creation mask 192is clear, is set. 193Otherwise, the mode bits represented by the specified 194.Ar who 195and 196.Ar perm 197values are set. 198.It \&\- 199If no value is supplied for 200.Ar perm , 201the ``\-'' operation has no effect. 202If no value is supplied for 203.Ar who , 204each permission bit specified in 205.Ar perm , 206for which the corresponding bit in the file mode creation mask 207is clear, is cleared. 208Otherwise, the mode bits represented by the specified 209.Ar who 210and 211.Ar perm 212values are cleared. 213.It = 214The mode bits specified by the 215.Ar who 216value are cleared, or, if no who value is specified, the owner, group 217and other mode bits are cleared. 218Then, if no value is supplied for 219.Ar who , 220each permission bit specified in 221.Ar perm , 222for which the corresponding bit in the file mode creation mask 223is clear, is set. 224Otherwise, the mode bits represented by the specified 225.Ar who 226and 227.Ar perm 228values are set. 229.El 230.Pp 231Each 232.Ar clause 233specifies one or more operations to be performed on the mode 234bits, and each operation is applied to the mode bits in the 235order specified. 236.Pp 237Operations upon the other permissions only (specified by the symbol 238``o'' by itself), in combination with the 239.Ar perm 240symbols ``s'' or ``t'', are ignored. 241.Sh EXAMPLES 242.Bl -tag -width "u=rwx,go=u-w" -compact 243.It Li 644 244make a file readable by anyone and writable by the owner only. 245.Pp 246.It Li go-w 247deny write permission to group and others. 248.Pp 249.It Li =rw,+X 250set the read and write permissions to the usual defaults, but 251retain any execute permissions that are currently set. 252.Pp 253.It Li +X 254make a directory or file searchable/executable by everyone if it is 255already searchable/executable by anyone. 256.Pp 257.It Li 755 258.It Li u=rwx,go=rx 259.It Li u=rwx,go=u-w 260make a file readable/executable by everyone and writable by the owner only. 261.Pp 262.It Li go= 263clear all mode bits for group and others. 264.Pp 265.It Li g=u-w 266set the group bits equal to the user bits, but clear the group write bit. 267.El 268.Sh SEE ALSO 269.Xr chflags 1 , 270.Xr install 1 , 271.Xr chmod 2 , 272.Xr stat 2 , 273.Xr umask 2 , 274.Xr fts 3 , 275.Xr setmode 3 , 276.Xr symlink 7 , 277.Xr chown 8 278.Sh STANDARDS 279The 280.Nm 281utility is expected to be 282.St -p1003.2-92 283compatible with the exception of the 284.Ar perm 285symbol 286.Dq t 287which is not included in that standard. 288.Sh BUGS 289There's no 290.Ar perm 291option for the naughty bits. 292