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35 .\" @(#)chmod.1 8.4 (Berkeley) 3/31/94
36 .\" $FreeBSD: src/bin/chmod/chmod.1,v 1.17.2.16 2003/02/24 03:01:00 trhodes Exp $
47 .Op Fl R Op Fl H | L | P
53 utility modifies the file mode bits of the listed files
58 The options are as follows:
59 .Bl -tag -width indent
61 Do not display a diagnostic message if
63 could not modify the mode for
65 nor modify the exit status to reflect such failures.
69 option is specified, symbolic links on the command line are followed.
70 (Symbolic links encountered in the tree traversal are not followed by
73 If the file is a symbolic link, change the mode of the link itself
74 rather than the file that the link points to.
78 option is specified, all symbolic links are followed.
82 option is specified, no symbolic links are followed.
85 Change the modes of the file hierarchies rooted in the files
86 instead of just the files themselves.
90 to be verbose, showing filenames as the mode is modified.
98 options are ignored unless the
101 In addition, these options override each other and the
102 command's actions are determined by the last one specified.
104 Only the owner of a file or the super-user is permitted to change
109 Modes may be absolute or symbolic.
110 An absolute mode is an octal number constructed from the sum of
111 one or more of the following values:
113 .Bl -tag -width 6n -compact -offset indent
116 Executable files with this bit set
117 will run with effective uid set to the uid of the file owner.
118 Directories with this bit set will force all files and
119 sub-directories created in them to be owned by the directory owner
120 and not by the uid of the creating process, if the underlying file
121 system supports this feature: see
129 Executable files with this bit set
130 will run with effective gid set to the gid of the file owner.
140 Allow write by owner.
142 For files, allow execution by owner.
143 For directories, allow the owner to
144 search in the directory.
146 Allow read by group members.
148 Allow write by group members.
150 For files, allow execution by group members.
151 For directories, allow
152 group members to search in the directory.
154 Allow read by others.
156 Allow write by others.
158 For files, allow execution by others.
159 For directories allow others to
160 search in the directory.
163 For example, the absolute mode that permits read, write and execute by
164 the owner, read and execute by group members, read and execute by
165 others, and no set-uid or set-gid behaviour is 755
166 (400+200+100+040+010+004+001).
168 The symbolic mode is described by the following grammar:
169 .Bd -literal -offset indent
170 mode ::= clause [, clause ...]
171 clause ::= [who ...] [action ...] action
172 action ::= op [perm ...]
173 who ::= a | u | g | o
175 perm ::= r | s | t | w | x | X | u | g | o
180 symbols ``u'', ``g'', and ``o'' specify the user, group, and other parts
181 of the mode bits, respectively.
184 symbol ``a'' is equivalent to ``ugo''.
188 symbols represent the portions of the mode bits as follows:
190 .Bl -tag -width Ds -compact -offset indent
194 The set-user-ID-on-execution and set-group-ID-on-execution bits.
200 The execute/search bits.
202 The execute/search bits if the file is a directory or any of the
203 execute/search bits are set in the original (unmodified) mode.
206 symbol ``X'' are only meaningful in conjunction with the
208 symbol ``+'', and are ignored in all other cases.
210 The user permission bits in the original mode of the file.
212 The group permission bits in the original mode of the file.
214 The other permission bits in the original mode of the file.
219 symbols represent the operation performed, as follows:
222 If no value is supplied for
224 the ``+'' operation has no effect.
225 If no value is supplied for
227 each permission bit specified in
229 for which the corresponding bit in the file mode creation mask
231 Otherwise, the mode bits represented by the specified
237 If no value is supplied for
239 the ``\-'' operation has no effect.
240 If no value is supplied for
242 each permission bit specified in
244 for which the corresponding bit in the file mode creation mask
245 is clear, is cleared.
246 Otherwise, the mode bits represented by the specified
252 The mode bits specified by the
254 value are cleared, or, if no who value is specified, the owner, group
255 and other mode bits are cleared.
256 Then, if no value is supplied for
258 each permission bit specified in
260 for which the corresponding bit in the file mode creation mask
262 Otherwise, the mode bits represented by the specified
271 specifies one or more operations to be performed on the mode
272 bits, and each operation is applied to the mode bits in the
275 Operations upon the other permissions only (specified by the symbol
276 ``o'' by itself), in combination with the
278 symbols ``s'' or ``t'', are ignored.
280 .Bl -tag -width "u=rwx,go=u-w" -compact
282 make a file readable by anyone and writable by the owner only.
285 deny write permission to group and others.
288 set the read and write permissions to the usual defaults, but
289 retain any execute permissions that are currently set.
292 make a directory or file searchable/executable by everyone if it is
293 already searchable/executable by anyone.
298 make a file readable/executable by everyone and writable by the owner only.
301 clear all mode bits for group and others.
304 set the group bits equal to the user bits, but clear the group write bit.
309 option for the naughty bits.
313 option is non-standard and its use in scripts is not recommended.
329 utility is expected to be
331 compatible with the exception of the
335 which is not included in that standard.