1.\"- 2.\" Copyright (c) 1989, 1990, 1993, 1994 3.\" The Regents of the University of California. All rights reserved. 4.\" 5.\" This code is derived from software contributed to Berkeley by 6.\" the Institute of Electrical and Electronics Engineers, Inc. 7.\" 8.\" Redistribution and use in source and binary forms, with or without 9.\" modification, are permitted provided that the following conditions 10.\" are met: 11.\" 1. Redistributions of source code must retain the above copyright 12.\" notice, this list of conditions and the following disclaimer. 13.\" 2. Redistributions in binary form must reproduce the above copyright 14.\" notice, this list of conditions and the following disclaimer in the 15.\" documentation and/or other materials provided with the distribution. 16.\" 4. Neither the name of the University nor the names of its contributors 17.\" may be used to endorse or promote products derived from this software 18.\" without specific prior written permission. 19.\" 20.\" THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND 21.\" ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 22.\" IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 23.\" ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE 24.\" FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 25.\" DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 26.\" OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 27.\" HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 28.\" LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 29.\" OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 30.\" SUCH DAMAGE. 31.\" 32.\" @(#)chmod.1 8.4 (Berkeley) 3/31/94 33.\" $FreeBSD$ 34.\" 35.Dd April 20, 2015 36.Dt CHMOD 1 37.Os 38.Sh NAME 39.Nm chmod 40.Nd change file modes 41.Sh SYNOPSIS 42.Nm 43.Op Fl fhv 44.Op Fl R Op Fl H | L | P 45.Ar mode 46.Ar 47.Sh DESCRIPTION 48The 49.Nm 50utility modifies the file mode bits of the listed files 51as specified by the 52.Ar mode 53operand. 54.Pp 55The options are as follows: 56.Bl -tag -width indent 57.It Fl f 58Do not display a diagnostic message if 59.Nm 60could not modify the mode for 61.Va file , 62nor modify the exit status to reflect such failures. 63.It Fl H 64If the 65.Fl R 66option is specified, symbolic links on the command line are followed 67and hence unaffected by the command. 68(Symbolic links encountered during tree traversal are not followed.) 69.It Fl h 70If the file is a symbolic link, change the mode of the link itself 71rather than the file that the link points to. 72.It Fl L 73If the 74.Fl R 75option is specified, all symbolic links are followed. 76.It Fl P 77If the 78.Fl R 79option is specified, no symbolic links are followed. 80This is the default. 81.It Fl R 82Change the modes of the file hierarchies rooted in the files, 83instead of just the files themselves. 84Beware of unintentionally matching the 85.Dq Pa ".." 86hard link to the parent directory when using wildcards like 87.Dq Li ".*" . 88.It Fl v 89Cause 90.Nm 91to be verbose, showing filenames as the mode is modified. 92If the 93.Fl v 94flag is specified more than once, the old and new modes of the file 95will also be printed, in both octal and symbolic notation. 96.El 97.Pp 98The 99.Fl H , 100.Fl L 101and 102.Fl P 103options are ignored unless the 104.Fl R 105option is specified. 106In addition, these options override each other and the 107command's actions are determined by the last one specified. 108.Pp 109Only the owner of a file or the super-user is permitted to change 110the mode of a file. 111.Sh EXIT STATUS 112.Ex -std 113.Sh MODES 114Modes may be absolute or symbolic. 115An absolute mode is an octal number constructed from the sum of 116one or more of the following values: 117.Pp 118.Bl -tag -width 6n -compact -offset indent 119.It Li 4000 120(the setuid bit). 121Executable files with this bit set 122will run with effective uid set to the uid of the file owner. 123Directories with this bit set will force all files and 124sub-directories created in them to be owned by the directory owner 125and not by the uid of the creating process, if the underlying file 126system supports this feature: see 127.Xr chmod 2 128and the 129.Cm suiddir 130option to 131.Xr mount 8 . 132.It Li 2000 133(the setgid bit). 134Executable files with this bit set 135will run with effective gid set to the gid of the file owner. 136.It Li 1000 137(the sticky bit). 138See 139.Xr chmod 2 140and 141.Xr sticky 7 . 142.It Li 0400 143Allow read by owner. 144.It Li 0200 145Allow write by owner. 146.It Li 0100 147For files, allow execution by owner. 148For directories, allow the owner to 149search in the directory. 150.It Li 0040 151Allow read by group members. 152.It Li 0020 153Allow write by group members. 154.It Li 0010 155For files, allow execution by group members. 156For directories, allow 157group members to search in the directory. 158.It Li 0004 159Allow read by others. 160.It Li 0002 161Allow write by others. 162.It Li 0001 163For files, allow execution by others. 164For directories allow others to 165search in the directory. 166.El 167.Pp 168For example, the absolute mode that permits read, write and execute by 169the owner, read and execute by group members, read and execute by 170others, and no set-uid or set-gid behaviour is 755 171(400+200+100+040+010+004+001). 172.Pp 173The symbolic mode is described by the following grammar: 174.Bd -literal -offset indent 175mode ::= clause [, clause ...] 176clause ::= [who ...] [action ...] action 177action ::= op [perm ...] 178who ::= a | u | g | o 179op ::= + | \- | = 180perm ::= r | s | t | w | x | X | u | g | o 181.Ed 182.Pp 183The 184.Ar who 185symbols ``u'', ``g'', and ``o'' specify the user, group, and other parts 186of the mode bits, respectively. 187The 188.Ar who 189symbol ``a'' is equivalent to ``ugo''. 190.Pp 191The 192.Ar perm 193symbols represent the portions of the mode bits as follows: 194.Pp 195.Bl -tag -width Ds -compact -offset indent 196.It r 197The read bits. 198.It s 199The set-user-ID-on-execution and set-group-ID-on-execution bits. 200.It t 201The sticky bit. 202.It w 203The write bits. 204.It x 205The execute/search bits. 206.It X 207The execute/search bits if the file is a directory or any of the 208execute/search bits are set in the original (unmodified) mode. 209Operations with the 210.Ar perm 211symbol ``X'' are only meaningful in conjunction with the 212.Ar op 213symbol ``+'', and are ignored in all other cases. 214.It u 215The user permission bits in the original mode of the file. 216.It g 217The group permission bits in the original mode of the file. 218.It o 219The other permission bits in the original mode of the file. 220.El 221.Pp 222The 223.Ar op 224symbols represent the operation performed, as follows: 225.Bl -tag -width 4n 226.It + 227If no value is supplied for 228.Ar perm , 229the ``+'' operation has no effect. 230If no value is supplied for 231.Ar who , 232each permission bit specified in 233.Ar perm , 234for which the corresponding bit in the file mode creation mask 235(see 236.Xr umask 2 ) 237is clear, is set. 238Otherwise, the mode bits represented by the specified 239.Ar who 240and 241.Ar perm 242values are set. 243.It \&\- 244If no value is supplied for 245.Ar perm , 246the ``\-'' operation has no effect. 247If no value is supplied for 248.Ar who , 249each permission bit specified in 250.Ar perm , 251for which the corresponding bit in the file mode creation mask 252is clear, is cleared. 253Otherwise, the mode bits represented by the specified 254.Ar who 255and 256.Ar perm 257values are cleared. 258.It = 259The mode bits specified by the 260.Ar who 261value are cleared, or, if no 262.Ar who 263value is specified, the owner, group 264and other mode bits are cleared. 265Then, if no value is supplied for 266.Ar who , 267each permission bit specified in 268.Ar perm , 269for which the corresponding bit in the file mode creation mask 270is clear, is set. 271Otherwise, the mode bits represented by the specified 272.Ar who 273and 274.Ar perm 275values are set. 276.El 277.Pp 278Each 279.Ar clause 280specifies one or more operations to be performed on the mode 281bits, and each operation is applied to the mode bits in the 282order specified. 283.Pp 284Operations upon the other permissions only (specified by the symbol 285``o'' by itself), in combination with the 286.Ar perm 287symbols ``s'' or ``t'', are ignored. 288.Pp 289The ``w'' permission on directories will permit file creation, relocation, 290and copy into that directory. 291Files created within the directory itself will inherit its group ID. 292.Sh EXAMPLES 293.Bl -tag -width "u=rwx,go=u-w" -compact 294.It Li 644 295make a file readable by anyone and writable by the owner only. 296.Pp 297.It Li go-w 298deny write permission to group and others. 299.Pp 300.It Li =rw,+X 301set the read and write permissions to the usual defaults, but 302retain any execute permissions that are currently set. 303.Pp 304.It Li +X 305make a directory or file searchable/executable by everyone if it is 306already searchable/executable by anyone. 307.Pp 308.It Li 755 309.It Li u=rwx,go=rx 310.It Li u=rwx,go=u-w 311make a file readable/executable by everyone and writable by the owner only. 312.Pp 313.It Li go= 314clear all mode bits for group and others. 315.Pp 316.It Li g=u-w 317set the group bits equal to the user bits, but clear the group write bit. 318.El 319.Sh COMPATIBILITY 320The 321.Fl v 322option is non-standard and its use in scripts is not recommended. 323.Sh SEE ALSO 324.Xr chflags 1 , 325.Xr install 1 , 326.Xr setfacl 1 , 327.Xr chmod 2 , 328.Xr stat 2 , 329.Xr umask 2 , 330.Xr fts 3 , 331.Xr setmode 3 , 332.Xr sticky 7 , 333.Xr symlink 7 , 334.Xr chown 8 , 335.Xr mount 8 336.Sh STANDARDS 337The 338.Nm 339utility is expected to be 340.St -p1003.2 341compatible with the exception of the 342.Ar perm 343symbol 344.Dq t 345which is not included in that standard. 346.Sh HISTORY 347A 348.Nm 349command appeared in 350.At v1 . 351.Sh BUGS 352There is no 353.Ar perm 354option for the naughty bits of a horse. 355