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) 130When set on a directory, unprivileged users can delete and rename 131only those files in the directory that are owned by them, regardless of 132the permissions on the directory. Under 133.Fx , 134the sticky bit is 135ignored for executable files and may only be set for directories (see 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. For directories, allow the owner to 143search in the directory. 144.It Li 0040 145Allow read by group members. 146.It Li 0020 147Allow write by group members. 148.It Li 0010 149For files, allow execution by group members. For directories, allow 150group members to search in the directory. 151.It Li 0004 152Allow read by others. 153.It Li 0002 154Allow write by others. 155.It Li 0001 156For files, allow execution by others. For directories allow others to 157search in the directory. 158.El 159.Pp 160For example, the absolute mode that permits read, write and execute by 161the owner, read and execute by group members, read and execute by 162others, and no set-uid or set-gid behaviour is 755 163(400+200+100+040+010+004+001). 164.Pp 165The symbolic mode is described by the following grammar: 166.Bd -literal -offset indent 167mode ::= clause [, clause ...] 168clause ::= [who ...] [action ...] action 169action ::= op [perm ...] 170who ::= a | u | g | o 171op ::= + | \- | = 172perm ::= r | s | t | w | x | X | u | g | o 173.Ed 174.Pp 175The 176.Ar who 177symbols ``u'', ``g'', and ``o'' specify the user, group, and other parts 178of the mode bits, respectively. 179The 180.Ar who 181symbol ``a'' is equivalent to ``ugo''. 182.Pp 183The 184.Ar perm 185symbols represent the portions of the mode bits as follows: 186.Pp 187.Bl -tag -width Ds -compact -offset indent 188.It r 189The read bits. 190.It s 191The set-user-ID-on-execution and set-group-ID-on-execution bits. 192.It t 193The sticky bit. 194.It w 195The write bits. 196.It x 197The execute/search bits. 198.It X 199The execute/search bits if the file is a directory or any of the 200execute/search bits are set in the original (unmodified) mode. 201Operations with the 202.Ar perm 203symbol ``X'' are only meaningful in conjunction with the 204.Ar op 205symbol ``+'', and are ignored in all other cases. 206.It u 207The user permission bits in the original mode of the file. 208.It g 209The group permission bits in the original mode of the file. 210.It o 211The other permission bits in the original mode of the file. 212.El 213.Pp 214The 215.Ar op 216symbols represent the operation performed, as follows: 217.Bl -tag -width 4n 218.It + 219If no value is supplied for 220.Ar perm , 221the ``+'' operation has no effect. 222If no value is supplied for 223.Ar who , 224each permission bit specified in 225.Ar perm , 226for which the corresponding bit in the file mode creation mask 227is clear, is set. 228Otherwise, the mode bits represented by the specified 229.Ar who 230and 231.Ar perm 232values are set. 233.It \&\- 234If no value is supplied for 235.Ar perm , 236the ``\-'' operation has no effect. 237If no value is supplied for 238.Ar who , 239each permission bit specified in 240.Ar perm , 241for which the corresponding bit in the file mode creation mask 242is clear, is cleared. 243Otherwise, the mode bits represented by the specified 244.Ar who 245and 246.Ar perm 247values are cleared. 248.It = 249The mode bits specified by the 250.Ar who 251value are cleared, or, if no who value is specified, the owner, group 252and other mode bits are cleared. 253Then, if 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.El 265.Pp 266Each 267.Ar clause 268specifies one or more operations to be performed on the mode 269bits, and each operation is applied to the mode bits in the 270order specified. 271.Pp 272Operations upon the other permissions only (specified by the symbol 273``o'' by itself), in combination with the 274.Ar perm 275symbols ``s'' or ``t'', are ignored. 276.Sh EXAMPLES 277.Bl -tag -width "u=rwx,go=u-w" -compact 278.It Li 644 279make a file readable by anyone and writable by the owner only. 280.Pp 281.It Li go-w 282deny write permission to group and others. 283.Pp 284.It Li =rw,+X 285set the read and write permissions to the usual defaults, but 286retain any execute permissions that are currently set. 287.Pp 288.It Li +X 289make a directory or file searchable/executable by everyone if it is 290already searchable/executable by anyone. 291.Pp 292.It Li 755 293.It Li u=rwx,go=rx 294.It Li u=rwx,go=u-w 295make a file readable/executable by everyone and writable by the owner only. 296.Pp 297.It Li go= 298clear all mode bits for group and others. 299.Pp 300.It Li g=u-w 301set the group bits equal to the user bits, but clear the group write bit. 302.El 303.Sh BUGS 304There's no 305.Ar perm 306option for the naughty bits. 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