1.\" Copyright (c) 1989, 1990, 1993, 1994 2.\" The Regents of the University of California. All rights reserved. 3.\" 4.\" This code is derived from software contributed to Berkeley by 5.\" the Institute of Electrical and Electronics Engineers, Inc. 6.\" 7.\" Redistribution and use in source and binary forms, with or without 8.\" modification, are permitted provided that the following conditions 9.\" are met: 10.\" 1. Redistributions of source code must retain the above copyright 11.\" notice, this list of conditions and the following disclaimer. 12.\" 2. Redistributions in binary form must reproduce the above copyright 13.\" notice, this list of conditions and the following disclaimer in the 14.\" documentation and/or other materials provided with the distribution. 15.\" 3. All advertising materials mentioning features or use of this software 16.\" must display the following acknowledgement: 17.\" This product includes software developed by the University of 18.\" California, Berkeley and its contributors. 19.\" 4. Neither the name of the University nor the names of its contributors 20.\" may be used to endorse or promote products derived from this software 21.\" without specific prior written permission. 22.\" 23.\" THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND 24.\" ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 25.\" IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 26.\" ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE 27.\" FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 28.\" DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 29.\" OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 30.\" HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 31.\" LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 32.\" OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 33.\" SUCH DAMAGE. 34.\" 35.\" @(#)chmod.1 8.4 (Berkeley) 3/31/94 36.\" 37.Dd March 31, 1994 38.Dt CHMOD 1 39.Os 40.Sh NAME 41.Nm chmod 42.Nd change file modes 43.Sh SYNOPSIS 44.Nm chmod 45.Oo 46.Fl R 47.Op Fl H | Fl L | Fl P 48.Oc 49.Ar mode 50.Ar file ... 51.Sh DESCRIPTION 52The 53.Nm chmod 54utility modifies the file mode bits of the listed files 55as specified by the 56.Ar mode 57operand. 58.Pp 59The options are as follows: 60.Bl -tag -width Ds 61.It Fl H 62If the 63.Fl R 64option is specified, symbolic links on the command line are followed. 65(Symbolic links encountered in the tree traversal are not followed.) 66.It Fl L 67If the 68.Fl R 69option is specified, all symbolic links are followed. 70.It Fl P 71If the 72.Fl R 73option is specified, no symbolic links are followed. 74.It Fl R 75Change the modes of the file hierarchies rooted in the files 76instead of just the files themselves. 77.El 78.Pp 79Symbolic links do not have modes, so unless the 80.Fl H 81or 82.Fl L 83option is set, 84.Nm chmod 85on a symbolic link always succeeds and has no effect. 86The 87.Fl H , 88.Fl L 89and 90.Fl P 91options are ignored unless the 92.Fl R 93option is specified. 94In addition, these options override each other and the 95command's actions are determined by the last one specified. 96.Pp 97Only the owner of a file or the super-user is permitted to change 98the mode of a file. 99.Pp 100The 101.Nm chmod 102utility exits 0 on success, and >0 if an error occurs. 103.Sh MODES 104Modes may be absolute or symbolic. 105An absolute mode is an octal number constructed by 106.Ar or-ing 107the following values: 108.Pp 109.Bl -tag -width 6n -compact -offset indent 110.It Li 4000 111set-user-ID-on-execution 112.It Li 2000 113set-group-ID-on-execution 114.It Li 1000 115sticky bit, see chmod(2) 116.It Li 0400 117read by owner 118.It Li 0200 119write by owner 120.It Li 0100 121execute (or search for directories) by owner 122.It Li 0070 123read, write, execute/search by group 124.It Li 0007 125read, write, execute/search by others 126.El 127.Pp 128The read, write, and execute/search values for group and others 129are encoded as described for owner. 130.Pp 131The symbolic mode is described by the following grammar: 132.Bd -literal -offset indent 133mode ::= clause [, clause ...] 134clause ::= [who ...] [action ...] last_action 135action ::= op [perm ...] 136last_action ::= op [perm ...] 137who ::= a | u | g | o 138op ::= + | \- | = 139perm ::= r | s | t | w | x | X | u | g | o 140.Ed 141.Pp 142The 143.Ar who 144symbols ``u'', ``g'', and ``o'' specify the user, group, and other parts 145of the mode bits, respectively. 146The 147.Ar who 148symbol ``a'' is equivalent to ``ugo''. 149.Pp 150.ne 1i 151The 152.Ar perm 153symbols represent the portions of the mode bits as follows: 154.Pp 155.Bl -tag -width Ds -compact -offset indent 156.It r 157The read bits. 158.It s 159The set-user-ID-on-execution and set-group-ID-on-execution bits. 160.It t 161The sticky bit. 162.It w 163The write bits. 164.It x 165The execute/search bits. 166.It X 167The execute/search bits if the file is a directory or any of the 168execute/search bits are set in the original (unmodified) mode. 169Operations with the 170.Ar perm 171symbol ``X'' are only meaningful in conjunction with the 172.Ar op 173symbol ``+'', and are ignored in all other cases. 174.It u 175The user permission bits in the mode of the original file. 176.It g 177The group permission bits in the mode of the original file. 178.It o 179The other permission bits in the mode of the original file. 180.El 181.Pp 182The 183.Ar op 184symbols represent the operation performed, as follows: 185.Bl -tag -width 4n 186.It + 187If no value is supplied for 188.Ar perm , 189the ``+'' operation has no effect. 190If no value is supplied for 191.Ar who , 192each permission bit specified in 193.Ar perm , 194for which the corresponding bit in the file mode creation mask 195is clear, is set. 196Otherwise, the mode bits represented by the specified 197.Ar who 198and 199.Ar perm 200values are set. 201.It \&\- 202If no value is supplied for 203.Ar perm , 204the ``\-'' operation has no effect. 205If no value is supplied for 206.Ar who , 207each permission bit specified in 208.Ar perm , 209for which the corresponding bit in the file mode creation mask 210is clear, is cleared. 211Otherwise, the mode bits represented by the specified 212.Ar who 213and 214.Ar perm 215values are cleared. 216.It = 217The mode bits specified by the 218.Ar who 219value are cleared, or, if no who value is specified, the owner, group 220and other mode bits are cleared. 221Then, if no value is supplied for 222.Ar who , 223each permission bit specified in 224.Ar perm , 225for which the corresponding bit in the file mode creation mask 226is clear, is set. 227Otherwise, the mode bits represented by the specified 228.Ar who 229and 230.Ar perm 231values are set. 232.El 233.Pp 234Each 235.Ar clause 236specifies one or more operations to be performed on the mode 237bits, and each operation is applied to the mode bits in the 238order specified. 239.Pp 240Operations upon the other permissions only (specified by the symbol 241``o'' by itself), in combination with the 242.Ar perm 243symbols ``s'' or ``t'', are ignored. 244.Sh EXAMPLES 245.Bl -tag -width "u=rwx,go=u-w" -compact 246.It Li 644 247make a file readable by anyone and writable by the owner only. 248.Pp 249.It Li go-w 250deny write permission to group and others. 251.Pp 252.It Li =rw,+X 253set the read and write permissions to the usual defaults, but 254retain any execute permissions that are currently set. 255.Pp 256.It Li +X 257make a directory or file searchable/executable by everyone if it is 258already searchable/executable by anyone. 259.Pp 260.It Li 755 261.It Li u=rwx,go=rx 262.It Li u=rwx,go=u-w 263make a file readable/executable by everyone and writable by the owner only. 264.Pp 265.It Li go= 266clear all mode bits for group and others. 267.Pp 268.It Li g=u-w 269set the group bits equal to the user bits, but clear the group write bit. 270.El 271.Sh BUGS 272There's no 273.Ar perm 274option for the naughty bits. 275.Sh SEE ALSO 276.Xr install 1 , 277.Xr chmod 2 , 278.Xr stat 2 , 279.Xr umask 2 , 280.Xr fts 3 , 281.Xr setmode 3 , 282.Xr symlink 7 , 283.Xr chown 8 284.Sh STANDARDS 285The 286.Nm chmod 287utility is expected to be POSIX 1003.2 288compatible with the exception of the 289.Ar perm 290symbols 291.Dq t 292and 293.Dq X 294which are not included in that standard. 295