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.\" $FreeBSD: src/bin/chmod/chmod.1,v 1.17.2.16 2003/02/24 03:01:00 trhodes Exp $ 37.\" $DragonFly: src/bin/chmod/chmod.1,v 1.3 2006/02/17 19:33:30 swildner Exp $ 38.\" 39.Dd March 31, 1994 40.Dt CHMOD 1 41.Os 42.Sh NAME 43.Nm chmod 44.Nd change file modes 45.Sh SYNOPSIS 46.Nm 47.Op Fl fhv 48.Op Fl R Op Fl H | L | P 49.Ar mode 50.Ar 51.Sh DESCRIPTION 52The 53.Nm 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 indent 61.It Fl f 62Do not display a diagnostic message if 63.Nm 64could not modify the mode for 65.Va file , 66nor modify the exit status to reflect such failures. 67.It Fl H 68If the 69.Fl R 70option is specified, symbolic links on the command line are followed. 71(Symbolic links encountered in the tree traversal are not followed by 72default.) 73.It Fl h 74If the file is a symbolic link, change the mode of the link itself 75rather than the file that the link points to. 76.It Fl L 77If the 78.Fl R 79option is specified, all symbolic links are followed. 80.It Fl P 81If the 82.Fl R 83option is specified, no symbolic links are followed. 84This is the default. 85.It Fl R 86Change the modes of the file hierarchies rooted in the files 87instead of just the files themselves. 88.It Fl v 89Cause 90.Nm 91to be verbose, showing filenames as the mode is modified. 92.El 93.Pp 94The 95.Fl H , 96.Fl L 97and 98.Fl P 99options are ignored unless the 100.Fl R 101option is specified. 102In addition, these options override each other and the 103command's actions are determined by the last one specified. 104.Pp 105Only the owner of a file or the super-user is permitted to change 106the mode of a file. 107.Sh EXAMPLES 108.Bl -tag -width "u=rwx,go=u-w" -compact 109.It Li 644 110make a file readable by anyone and writable by the owner only. 111.Pp 112.It Li go-w 113deny write permission to group and others. 114.Pp 115.It Li =rw,+X 116set the read and write permissions to the usual defaults, but 117retain any execute permissions that are currently set. 118.Pp 119.It Li +X 120make a directory or file searchable/executable by everyone if it is 121already searchable/executable by anyone. 122.Pp 123.It Li 755 124.It Li u=rwx,go=rx 125.It Li u=rwx,go=u-w 126make a file readable/executable by everyone and writable by the owner only. 127.Pp 128.It Li go= 129clear all mode bits for group and others. 130.Pp 131.It Li g=u-w 132set the group bits equal to the user bits, but clear the group write bit. 133.El 134.Sh DIAGNOSTICS 135.Ex -std 136.Sh MODES 137Modes may be absolute or symbolic. 138An absolute mode is an octal number constructed from the sum of 139one or more of the following values: 140.Pp 141.Bl -tag -width 6n -compact -offset indent 142.It Li 4000 143(the setuid bit). 144Executable files with this bit set 145will run with effective uid set to the uid of the file owner. 146Directories with this bit set will force all files and 147sub-directories created in them to be owned by the directory owner 148and not by the uid of the creating process, if the underlying file 149system supports this feature: see 150.Xr chmod 2 151and the 152.Cm suiddir 153option to 154.Xr mount 8 . 155.It Li 2000 156(the setgid bit). 157Executable files with this bit set 158will run with effective gid set to the gid of the file owner. 159.It Li 1000 160(the sticky bit). 161See 162.Xr chmod 2 163and 164.Xr sticky 8 . 165.It Li 0400 166Allow read by owner. 167.It Li 0200 168Allow write by owner. 169.It Li 0100 170For files, allow execution by owner. 171For directories, allow the owner to 172search in the directory. 173.It Li 0040 174Allow read by group members. 175.It Li 0020 176Allow write by group members. 177.It Li 0010 178For files, allow execution by group members. 179For directories, allow 180group members to search in the directory. 181.It Li 0004 182Allow read by others. 183.It Li 0002 184Allow write by others. 185.It Li 0001 186For files, allow execution by others. 187For directories allow others to 188search in the directory. 189.El 190.Pp 191For example, the absolute mode that permits read, write and execute by 192the owner, read and execute by group members, read and execute by 193others, and no set-uid or set-gid behaviour is 755 194(400+200+100+040+010+004+001). 195.Pp 196The symbolic mode is described by the following grammar: 197.Bd -literal -offset indent 198mode ::= clause [, clause ...] 199clause ::= [who ...] [action ...] action 200action ::= op [perm ...] 201who ::= a | u | g | o 202op ::= + | \- | = 203perm ::= r | s | t | w | x | X | u | g | o 204.Ed 205.Pp 206The 207.Ar who 208symbols ``u'', ``g'', and ``o'' specify the user, group, and other parts 209of the mode bits, respectively. 210The 211.Ar who 212symbol ``a'' is equivalent to ``ugo''. 213.Pp 214The 215.Ar perm 216symbols represent the portions of the mode bits as follows: 217.Pp 218.Bl -tag -width Ds -compact -offset indent 219.It r 220The read bits. 221.It s 222The set-user-ID-on-execution and set-group-ID-on-execution bits. 223.It t 224The sticky bit. 225.It w 226The write bits. 227.It x 228The execute/search bits. 229.It X 230The execute/search bits if the file is a directory or any of the 231execute/search bits are set in the original (unmodified) mode. 232Operations with the 233.Ar perm 234symbol ``X'' are only meaningful in conjunction with the 235.Ar op 236symbol ``+'', and are ignored in all other cases. 237.It u 238The user permission bits in the original mode of the file. 239.It g 240The group permission bits in the original mode of the file. 241.It o 242The other permission bits in the original mode of the file. 243.El 244.Pp 245The 246.Ar op 247symbols represent the operation performed, as follows: 248.Bl -tag -width 4n 249.It + 250If no value is supplied for 251.Ar perm , 252the ``+'' operation has no effect. 253If no value is supplied for 254.Ar who , 255each permission bit specified in 256.Ar perm , 257for which the corresponding bit in the file mode creation mask 258is clear, is set. 259Otherwise, the mode bits represented by the specified 260.Ar who 261and 262.Ar perm 263values are set. 264.It \&\- 265If no value is supplied for 266.Ar perm , 267the ``\-'' operation has no effect. 268If no value is supplied for 269.Ar who , 270each permission bit specified in 271.Ar perm , 272for which the corresponding bit in the file mode creation mask 273is clear, is cleared. 274Otherwise, the mode bits represented by the specified 275.Ar who 276and 277.Ar perm 278values are cleared. 279.It = 280The mode bits specified by the 281.Ar who 282value are cleared, or, if no who value is specified, the owner, group 283and other mode bits are cleared. 284Then, if no value is supplied for 285.Ar who , 286each permission bit specified in 287.Ar perm , 288for which the corresponding bit in the file mode creation mask 289is clear, is set. 290Otherwise, the mode bits represented by the specified 291.Ar who 292and 293.Ar perm 294values are set. 295.El 296.Pp 297Each 298.Ar clause 299specifies one or more operations to be performed on the mode 300bits, and each operation is applied to the mode bits in the 301order specified. 302.Pp 303Operations upon the other permissions only (specified by the symbol 304``o'' by itself), in combination with the 305.Ar perm 306symbols ``s'' or ``t'', are ignored. 307.Sh COMPATIBILITY 308The 309.Fl v 310option is non-standard and its use in scripts is not recommended. 311.Sh SEE ALSO 312.Xr chflags 1 , 313.Xr install 1 , 314.Xr chmod 2 , 315.Xr stat 2 , 316.Xr umask 2 , 317.Xr fts 3 , 318.Xr setmode 3 , 319.Xr symlink 7 , 320.Xr chown 8 , 321.Xr mount 8 , 322.Xr sticky 8 323.Sh STANDARDS 324The 325.Nm 326utility is expected to be 327.St -p1003.2 328compatible with the exception of the 329.Ar perm 330symbol 331.Dq t 332which is not included in that standard. 333.Sh HISTORY 334A 335.Nm 336command appeared in 337.At v1 . 338.Sh BUGS 339There's no 340.Ar perm 341option for the naughty bits. 342