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.\" 4. Neither the name of the University nor the names of its contributors 16.\" may be used to endorse or promote products derived from this software 17.\" without specific prior written permission. 18.\" 19.\" THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND 20.\" ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 21.\" IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 22.\" ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE 23.\" FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 24.\" DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 25.\" OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 26.\" HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 27.\" LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 28.\" OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 29.\" SUCH DAMAGE. 30.\" 31.\" @(#)chmod.1 8.4 (Berkeley) 3/31/94 32.\" $FreeBSD$ 33.\" 34.Dd March 31, 1994 35.Dt CHMOD 1 36.Os 37.Sh NAME 38.Nm chmod 39.Nd change file modes 40.Sh SYNOPSIS 41.Nm 42.Op Fl fhv 43.Op Fl R Op Fl H | L | P 44.Ar mode 45.Ar 46.Sh DESCRIPTION 47The 48.Nm 49utility modifies the file mode bits of the listed files 50as specified by the 51.Ar mode 52operand. 53.Pp 54The options are as follows: 55.Bl -tag -width indent 56.It Fl f 57Do not display a diagnostic message if 58.Nm 59could not modify the mode for 60.Va file , 61nor modify the exit status to reflect such failures. 62.It Fl H 63If the 64.Fl R 65option is specified, symbolic links on the command line are followed. 66(Symbolic links encountered in the tree traversal are not followed by 67default.) 68.It Fl h 69If the file is a symbolic link, change the mode of the link itself 70rather than the file that the link points to. 71.It Fl L 72If the 73.Fl R 74option is specified, all symbolic links are followed. 75.It Fl P 76If the 77.Fl R 78option is specified, no symbolic links are followed. 79This is the default. 80.It Fl R 81Change the modes of the file hierarchies rooted in the files 82instead of just the files themselves. 83.It Fl v 84Cause 85.Nm 86to be verbose, showing filenames as the mode is modified. 87If the 88.Fl v 89flag is specified more than once, the old and new modes of the file 90will also be printed, in both octal and symbolic notation. 91.El 92.Pp 93The 94.Fl H , 95.Fl L 96and 97.Fl P 98options are ignored unless the 99.Fl R 100option is specified. 101In addition, these options override each other and the 102command's actions are determined by the last one specified. 103.Pp 104Only the owner of a file or the super-user is permitted to change 105the mode of a file. 106.Sh DIAGNOSTICS 107.Ex -std 108.Sh MODES 109Modes may be absolute or symbolic. 110An absolute mode is an octal number constructed from the sum of 111one or more of the following values: 112.Pp 113.Bl -tag -width 6n -compact -offset indent 114.It Li 4000 115(the setuid bit). 116Executable files with this bit set 117will run with effective uid set to the uid of the file owner. 118Directories with this bit set will force all files and 119sub-directories created in them to be owned by the directory owner 120and not by the uid of the creating process, if the underlying file 121system supports this feature: see 122.Xr chmod 2 123and the 124.Cm suiddir 125option to 126.Xr mount 8 . 127.It Li 2000 128(the setgid bit). 129Executable files with this bit set 130will run with effective gid set to the gid of the file owner. 131.It Li 1000 132(the sticky bit). 133See 134.Xr chmod 2 135and 136.Xr sticky 8 . 137.It Li 0400 138Allow read by owner. 139.It Li 0200 140Allow write by owner. 141.It Li 0100 142For files, allow execution by owner. 143For directories, allow the owner to 144search in the directory. 145.It Li 0040 146Allow read by group members. 147.It Li 0020 148Allow write by group members. 149.It Li 0010 150For files, allow execution by group members. 151For directories, allow 152group members to search in the directory. 153.It Li 0004 154Allow read by others. 155.It Li 0002 156Allow write by others. 157.It Li 0001 158For files, allow execution by others. 159For directories allow others to 160search in the directory. 161.El 162.Pp 163For example, the absolute mode that permits read, write and execute by 164the owner, read and execute by group members, read and execute by 165others, and no set-uid or set-gid behaviour is 755 166(400+200+100+040+010+004+001). 167.Pp 168The symbolic mode is described by the following grammar: 169.Bd -literal -offset indent 170mode ::= clause [, clause ...] 171clause ::= [who ...] [action ...] action 172action ::= op [perm ...] 173who ::= a | u | g | o 174op ::= + | \- | = 175perm ::= r | s | t | w | x | X | u | g | o 176.Ed 177.Pp 178The 179.Ar who 180symbols ``u'', ``g'', and ``o'' specify the user, group, and other parts 181of the mode bits, respectively. 182The 183.Ar who 184symbol ``a'' is equivalent to ``ugo''. 185.Pp 186The 187.Ar perm 188symbols represent the portions of the mode bits as follows: 189.Pp 190.Bl -tag -width Ds -compact -offset indent 191.It r 192The read bits. 193.It s 194The set-user-ID-on-execution and set-group-ID-on-execution bits. 195.It t 196The sticky bit. 197.It w 198The write bits. 199.It x 200The execute/search bits. 201.It X 202The execute/search bits if the file is a directory or any of the 203execute/search bits are set in the original (unmodified) mode. 204Operations with the 205.Ar perm 206symbol ``X'' are only meaningful in conjunction with the 207.Ar op 208symbol ``+'', and are ignored in all other cases. 209.It u 210The user permission bits in the original mode of the file. 211.It g 212The group permission bits in the original mode of the file. 213.It o 214The other permission bits in the original mode of the file. 215.El 216.Pp 217The 218.Ar op 219symbols represent the operation performed, as follows: 220.Bl -tag -width 4n 221.It + 222If no value is supplied for 223.Ar perm , 224the ``+'' operation has no effect. 225If no value is supplied for 226.Ar who , 227each permission bit specified in 228.Ar perm , 229for which the corresponding bit in the file mode creation mask 230is clear, is set. 231Otherwise, the mode bits represented by the specified 232.Ar who 233and 234.Ar perm 235values are set. 236.It \&\- 237If no value is supplied for 238.Ar perm , 239the ``\-'' operation has no effect. 240If no value is supplied for 241.Ar who , 242each permission bit specified in 243.Ar perm , 244for which the corresponding bit in the file mode creation mask 245is clear, is cleared. 246Otherwise, the mode bits represented by the specified 247.Ar who 248and 249.Ar perm 250values are cleared. 251.It = 252The mode bits specified by the 253.Ar who 254value are cleared, or, if no who value is specified, the owner, group 255and other mode bits are cleared. 256Then, if no value is supplied for 257.Ar who , 258each permission bit specified in 259.Ar perm , 260for which the corresponding bit in the file mode creation mask 261is clear, is set. 262Otherwise, the mode bits represented by the specified 263.Ar who 264and 265.Ar perm 266values are set. 267.El 268.Pp 269Each 270.Ar clause 271specifies one or more operations to be performed on the mode 272bits, and each operation is applied to the mode bits in the 273order specified. 274.Pp 275Operations upon the other permissions only (specified by the symbol 276``o'' by itself), in combination with the 277.Ar perm 278symbols ``s'' or ``t'', are ignored. 279.Sh EXAMPLES 280.Bl -tag -width "u=rwx,go=u-w" -compact 281.It Li 644 282make a file readable by anyone and writable by the owner only. 283.Pp 284.It Li go-w 285deny write permission to group and others. 286.Pp 287.It Li =rw,+X 288set the read and write permissions to the usual defaults, but 289retain any execute permissions that are currently set. 290.Pp 291.It Li +X 292make a directory or file searchable/executable by everyone if it is 293already searchable/executable by anyone. 294.Pp 295.It Li 755 296.It Li u=rwx,go=rx 297.It Li u=rwx,go=u-w 298make a file readable/executable by everyone and writable by the owner only. 299.Pp 300.It Li go= 301clear all mode bits for group and others. 302.Pp 303.It Li g=u-w 304set the group bits equal to the user bits, but clear the group write bit. 305.El 306.Sh BUGS 307There's no 308.Ar perm 309option for the naughty bits. 310.Sh COMPATIBILITY 311The 312.Fl v 313option is non-standard and its use in scripts is not recommended. 314.Sh SEE ALSO 315.Xr chflags 1 , 316.Xr install 1 , 317.Xr setfacl 1 , 318.Xr chmod 2 , 319.Xr stat 2 , 320.Xr umask 2 , 321.Xr fts 3 , 322.Xr setmode 3 , 323.Xr symlink 7 , 324.Xr chown 8 , 325.Xr mount 8 , 326.Xr sticky 8 327.Sh STANDARDS 328The 329.Nm 330utility is expected to be 331.St -p1003.2 332compatible with the exception of the 333.Ar perm 334symbol 335.Dq t 336which is not included in that standard. 337.Sh HISTORY 338A 339.Nm 340command appeared in 341.At v1 . 342