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 indent 60.It Fl f 61Do not display a diagnostic message if 62.Nm 63could not modify the mode for 64.Va file , 65nor modify the exit status to reflect such failures. 66.It Fl H 67If the 68.Fl R 69option is specified, symbolic links on the command line are followed. 70(Symbolic links encountered in the tree traversal are not followed by 71default.) 72.It Fl h 73If the file is a symbolic link, change the mode of the link itself 74rather than the file that the link points to. 75.It Fl L 76If the 77.Fl R 78option is specified, all symbolic links are followed. 79.It Fl P 80If the 81.Fl R 82option is specified, no symbolic links are followed. 83This is the default. 84.It Fl R 85Change the modes of the file hierarchies rooted in the files 86instead of just the files themselves. 87.It Fl v 88Cause 89.Nm 90to be verbose, showing filenames as the mode is modified. 91If the 92.Fl v 93flag is specified more than once, the old and new modes of the file 94will also be printed, in both octal and symbolic notation. 95.El 96.Pp 97The 98.Fl H , 99.Fl L 100and 101.Fl P 102options are ignored unless the 103.Fl R 104option is specified. 105In addition, these options override each other and the 106command's actions are determined by the last one specified. 107.Pp 108Only the owner of a file or the super-user is permitted to change 109the mode of a file. 110.Sh DIAGNOSTICS 111.Ex -std 112.Sh MODES 113Modes may be absolute or symbolic. 114An absolute mode is an octal number constructed from the sum of 115one or more of the following values: 116.Pp 117.Bl -tag -width 6n -compact -offset indent 118.It Li 4000 119(the setuid bit). 120Executable files with this bit set 121will run with effective uid set to the uid of the file owner. 122Directories with this bit set will force all files and 123sub-directories created in them to be owned by the directory owner 124and not by the uid of the creating process, if the underlying file 125system supports this feature: see 126.Xr chmod 2 127and the 128.Cm suiddir 129option to 130.Xr mount 8 . 131.It Li 2000 132(the setgid bit). 133Executable files with this bit set 134will run with effective gid set to the gid of the file owner. 135.It Li 1000 136(the sticky bit). 137See 138.Xr chmod 2 139and 140.Xr sticky 8 . 141.It Li 0400 142Allow read by owner. 143.It Li 0200 144Allow write by owner. 145.It Li 0100 146For files, allow execution by owner. 147For directories, allow the owner to 148search in the directory. 149.It Li 0040 150Allow read by group members. 151.It Li 0020 152Allow write by group members. 153.It Li 0010 154For files, allow execution by group members. 155For directories, allow 156group members to search in the directory. 157.It Li 0004 158Allow read by others. 159.It Li 0002 160Allow write by others. 161.It Li 0001 162For files, allow execution by others. 163For directories allow others to 164search in the directory. 165.El 166.Pp 167For example, the absolute mode that permits read, write and execute by 168the owner, read and execute by group members, read and execute by 169others, and no set-uid or set-gid behaviour is 755 170(400+200+100+040+010+004+001). 171.Pp 172The symbolic mode is described by the following grammar: 173.Bd -literal -offset indent 174mode ::= clause [, clause ...] 175clause ::= [who ...] [action ...] action 176action ::= op [perm ...] 177who ::= a | u | g | o 178op ::= + | \- | = 179perm ::= r | s | t | w | x | X | u | g | o 180.Ed 181.Pp 182The 183.Ar who 184symbols ``u'', ``g'', and ``o'' specify the user, group, and other parts 185of the mode bits, respectively. 186The 187.Ar who 188symbol ``a'' is equivalent to ``ugo''. 189.Pp 190The 191.Ar perm 192symbols represent the portions of the mode bits as follows: 193.Pp 194.Bl -tag -width Ds -compact -offset indent 195.It r 196The read bits. 197.It s 198The set-user-ID-on-execution and set-group-ID-on-execution bits. 199.It t 200The sticky bit. 201.It w 202The write bits. 203.It x 204The execute/search bits. 205.It X 206The execute/search bits if the file is a directory or any of the 207execute/search bits are set in the original (unmodified) mode. 208Operations with the 209.Ar perm 210symbol ``X'' are only meaningful in conjunction with the 211.Ar op 212symbol ``+'', and are ignored in all other cases. 213.It u 214The user permission bits in the original mode of the file. 215.It g 216The group permission bits in the original mode of the file. 217.It o 218The other permission bits in the original mode of the file. 219.El 220.Pp 221The 222.Ar op 223symbols represent the operation performed, as follows: 224.Bl -tag -width 4n 225.It + 226If no value is supplied for 227.Ar perm , 228the ``+'' operation has no effect. 229If no value is supplied for 230.Ar who , 231each permission bit specified in 232.Ar perm , 233for which the corresponding bit in the file mode creation mask 234is clear, is set. 235Otherwise, the mode bits represented by the specified 236.Ar who 237and 238.Ar perm 239values are set. 240.It \&\- 241If no value is supplied for 242.Ar perm , 243the ``\-'' operation has no effect. 244If no value is supplied for 245.Ar who , 246each permission bit specified in 247.Ar perm , 248for which the corresponding bit in the file mode creation mask 249is clear, is cleared. 250Otherwise, the mode bits represented by the specified 251.Ar who 252and 253.Ar perm 254values are cleared. 255.It = 256The mode bits specified by the 257.Ar who 258value are cleared, or, if no who value is specified, the owner, group 259and other mode bits are cleared. 260Then, if no value is supplied for 261.Ar who , 262each permission bit specified in 263.Ar perm , 264for which the corresponding bit in the file mode creation mask 265is clear, is set. 266Otherwise, the mode bits represented by the specified 267.Ar who 268and 269.Ar perm 270values are set. 271.El 272.Pp 273Each 274.Ar clause 275specifies one or more operations to be performed on the mode 276bits, and each operation is applied to the mode bits in the 277order specified. 278.Pp 279Operations upon the other permissions only (specified by the symbol 280``o'' by itself), in combination with the 281.Ar perm 282symbols ``s'' or ``t'', are ignored. 283.Sh EXAMPLES 284.Bl -tag -width "u=rwx,go=u-w" -compact 285.It Li 644 286make a file readable by anyone and writable by the owner only. 287.Pp 288.It Li go-w 289deny write permission to group and others. 290.Pp 291.It Li =rw,+X 292set the read and write permissions to the usual defaults, but 293retain any execute permissions that are currently set. 294.Pp 295.It Li +X 296make a directory or file searchable/executable by everyone if it is 297already searchable/executable by anyone. 298.Pp 299.It Li 755 300.It Li u=rwx,go=rx 301.It Li u=rwx,go=u-w 302make a file readable/executable by everyone and writable by the owner only. 303.Pp 304.It Li go= 305clear all mode bits for group and others. 306.Pp 307.It Li g=u-w 308set the group bits equal to the user bits, but clear the group write bit. 309.El 310.Sh BUGS 311There's no 312.Ar perm 313option for the naughty bits. 314.Sh COMPATIBILITY 315The 316.Fl v 317option is non-standard and its use in scripts is not recommended. 318.Sh SEE ALSO 319.Xr chflags 1 , 320.Xr install 1 , 321.Xr setfacl 1 , 322.Xr chmod 2 , 323.Xr stat 2 , 324.Xr umask 2 , 325.Xr fts 3 , 326.Xr setmode 3 , 327.Xr symlink 7 , 328.Xr chown 8 , 329.Xr mount 8 , 330.Xr sticky 8 331.Sh STANDARDS 332The 333.Nm 334utility is expected to be 335.St -p1003.2 336compatible with the exception of the 337.Ar perm 338symbol 339.Dq t 340which is not included in that standard. 341.Sh HISTORY 342A 343.Nm 344command appeared in 345.At v1 . 346