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.\" $FreeBSD$ 37.\" 38.Dd March 31, 1994 39.Dt CHMOD 1 40.Os 41.Sh NAME 42.Nm chmod 43.Nd change file modes 44.Sh SYNOPSIS 45.Nm 46.Op Fl fhv 47.Op Fl R Op Fl H | L | P 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 by 65default.) 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. 74This is the default. 75.It Fl R 76Change the modes of the file hierarchies rooted in the files 77instead of just the files themselves. 78.It Fl f 79Do not display a diagnostic message if 80.Nm 81could not modify the mode for 82.Va file . 83.It Fl h 84If the file is a symbolic link, change the mode of the link itself 85rather than the file that the link points to. 86.It Fl v 87Cause 88.Nm 89to be verbose, showing files as the mode is modified. 90.El 91.Pp 92The 93.Fl H , 94.Fl L 95and 96.Fl P 97options are ignored unless the 98.Fl R 99option is specified. 100In addition, these options override each other and the 101command's actions are determined by the last one specified. 102.Pp 103Only the owner of a file or the super-user is permitted to change 104the mode of a file. 105.Sh DIAGNOSTICS 106.Ex -std 107.Sh MODES 108Modes may be absolute or symbolic. 109An absolute mode is an octal number constructed from the sum of 110one or more of the following values: 111.Pp 112.Bl -tag -width 6n -compact -offset indent 113.It Li 4000 114(the set-user-ID-on-execution bit) Executable files with this bit set 115will run with effective uid set to the uid of the file owner. 116Directories with the set-user-id bit set will force all files and 117sub-directories created in them to be owned by the directory owner 118and not by the uid of the creating process, if the underlying file 119system supports this feature: see 120.Xr chmod 2 121and the 122.Ar suiddir 123option to 124.Xr mount 8 . 125.It Li 2000 126(the set-group-ID-on-execution bit) Executable files with this bit set 127will run with effective gid set to the gid of the file owner. 128.It Li 1000 129(the sticky bit) 130See 131.Xr chmod 2 132and 133.Xr sticky 8 . 134.It Li 0400 135Allow read by owner. 136.It Li 0200 137Allow write by owner. 138.It Li 0100 139For files, allow execution by owner. For directories, allow the owner to 140search in the directory. 141.It Li 0040 142Allow read by group members. 143.It Li 0020 144Allow write by group members. 145.It Li 0010 146For files, allow execution by group members. For directories, allow 147group members to search in the directory. 148.It Li 0004 149Allow read by others. 150.It Li 0002 151Allow write by others. 152.It Li 0001 153For files, allow execution by others. For directories allow others to 154search in the directory. 155.El 156.Pp 157For example, the absolute mode that permits read, write and execute by 158the owner, read and execute by group members, read and execute by 159others, and no set-uid or set-gid behaviour is 755 160(400+200+100+040+010+004+001). 161.Pp 162The symbolic mode is described by the following grammar: 163.Bd -literal -offset indent 164mode ::= clause [, clause ...] 165clause ::= [who ...] [action ...] action 166action ::= op [perm ...] 167who ::= a | u | g | o 168op ::= + | \- | = 169perm ::= r | s | t | w | x | X | u | g | o 170.Ed 171.Pp 172The 173.Ar who 174symbols ``u'', ``g'', and ``o'' specify the user, group, and other parts 175of the mode bits, respectively. 176The 177.Ar who 178symbol ``a'' is equivalent to ``ugo''. 179.Pp 180The 181.Ar perm 182symbols represent the portions of the mode bits as follows: 183.Pp 184.Bl -tag -width Ds -compact -offset indent 185.It r 186The read bits. 187.It s 188The set-user-ID-on-execution and set-group-ID-on-execution bits. 189.It t 190The sticky bit. 191.It w 192The write bits. 193.It x 194The execute/search bits. 195.It X 196The execute/search bits if the file is a directory or any of the 197execute/search bits are set in the original (unmodified) mode. 198Operations with the 199.Ar perm 200symbol ``X'' are only meaningful in conjunction with the 201.Ar op 202symbol ``+'', and are ignored in all other cases. 203.It u 204The user permission bits in the original mode of the file. 205.It g 206The group permission bits in the original mode of the file. 207.It o 208The other permission bits in the original mode of the file. 209.El 210.Pp 211The 212.Ar op 213symbols represent the operation performed, as follows: 214.Bl -tag -width 4n 215.It + 216If no value is supplied for 217.Ar perm , 218the ``+'' operation has no effect. 219If no value is supplied for 220.Ar who , 221each permission bit specified in 222.Ar perm , 223for which the corresponding bit in the file mode creation mask 224is clear, is set. 225Otherwise, the mode bits represented by the specified 226.Ar who 227and 228.Ar perm 229values are set. 230.It \&\- 231If no value is supplied for 232.Ar perm , 233the ``\-'' operation has no effect. 234If no value is supplied for 235.Ar who , 236each permission bit specified in 237.Ar perm , 238for which the corresponding bit in the file mode creation mask 239is clear, is cleared. 240Otherwise, the mode bits represented by the specified 241.Ar who 242and 243.Ar perm 244values are cleared. 245.It = 246The mode bits specified by the 247.Ar who 248value are cleared, or, if no who value is specified, the owner, group 249and other mode bits are cleared. 250Then, if no value is supplied for 251.Ar who , 252each permission bit specified in 253.Ar perm , 254for which the corresponding bit in the file mode creation mask 255is clear, is set. 256Otherwise, the mode bits represented by the specified 257.Ar who 258and 259.Ar perm 260values are set. 261.El 262.Pp 263Each 264.Ar clause 265specifies one or more operations to be performed on the mode 266bits, and each operation is applied to the mode bits in the 267order specified. 268.Pp 269Operations upon the other permissions only (specified by the symbol 270``o'' by itself), in combination with the 271.Ar perm 272symbols ``s'' or ``t'', are ignored. 273.Sh EXAMPLES 274.Bl -tag -width "u=rwx,go=u-w" -compact 275.It Li 644 276make a file readable by anyone and writable by the owner only. 277.Pp 278.It Li go-w 279deny write permission to group and others. 280.Pp 281.It Li =rw,+X 282set the read and write permissions to the usual defaults, but 283retain any execute permissions that are currently set. 284.Pp 285.It Li +X 286make a directory or file searchable/executable by everyone if it is 287already searchable/executable by anyone. 288.Pp 289.It Li 755 290.It Li u=rwx,go=rx 291.It Li u=rwx,go=u-w 292make a file readable/executable by everyone and writable by the owner only. 293.Pp 294.It Li go= 295clear all mode bits for group and others. 296.Pp 297.It Li g=u-w 298set the group bits equal to the user bits, but clear the group write bit. 299.El 300.Sh BUGS 301There's no 302.Ar perm 303option for the naughty bits. 304.Sh COMPATIBILITY 305The 306.Fl v 307option is non-standard and its use in scripts is not recommended. 308.Sh SEE ALSO 309.Xr chflags 1 , 310.Xr install 1 , 311.Xr chmod 2 , 312.Xr stat 2 , 313.Xr umask 2 , 314.Xr fts 3 , 315.Xr setmode 3 , 316.Xr symlink 7 , 317.Xr chown 8 , 318.Xr mount 8 , 319.Xr sticky 8 320.Sh STANDARDS 321The 322.Nm 323utility is expected to be 324.St -p1003.2 325compatible with the exception of the 326.Ar perm 327symbol 328.Dq t 329which is not included in that standard. 330.Sh HISTORY 331A 332.Nm 333command appeared in 334.At v1 . 335