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35 .\" @(#)chmod.1 8.4 (Berkeley) 3/31/94
36 .\" $FreeBSD: src/bin/chmod/chmod.1,v 1.33 2002/10/01 20:32:59 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:
63 option is specified, symbolic links on the command line are followed.
64 (Symbolic links encountered in the tree traversal are not followed by
69 option is specified, all symbolic links are followed.
73 option is specified, no symbolic links are followed.
76 Change the modes of the file hierarchies rooted in the files
77 instead of just the files themselves.
79 Do not display a diagnostic message if
81 could not modify the mode for
86 to be verbose, showing filenames as the mode is modified.
89 flag is specified more than once, the old and new modes of the file
90 will also be printed, in both octal and symbolic notation.
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
115 (the set-user-ID-on-execution bit) Executable files with this bit set
116 will run with effective uid set to the uid of the file owner.
117 Directories with the set-user-id bit set will force all files and
118 sub-directories created in them to be owned by the directory owner
119 and not by the uid of the creating process, if the underlying file
120 system supports this feature: see
127 (the set-group-ID-on-execution bit) Executable files with this bit set
128 will run with effective gid set to the gid of the file owner.
138 Allow write by owner.
140 For files, allow execution by owner.
141 For directories, allow the owner to
142 search in the directory.
144 Allow read by group members.
146 Allow write by group members.
148 For files, allow execution by group members.
149 For directories, allow
150 group members to search in the directory.
152 Allow read by others.
154 Allow write by others.
156 For files, allow execution by others.
157 For directories allow others to
158 search in the directory.
161 For example, the absolute mode that permits read, write and execute by
162 the owner, read and execute by group members, read and execute by
163 others, and no set-uid or set-gid behaviour is 755
164 (400+200+100+040+010+004+001).
166 The symbolic mode is described by the following grammar:
167 .Bd -literal -offset indent
168 mode ::= clause [, clause ...]
169 clause ::= [who ...] [action ...] action
170 action ::= op [perm ...]
171 who ::= a | u | g | o
173 perm ::= r | s | t | w | x | X | u | g | o
178 symbols ``u'', ``g'', and ``o'' specify the user, group, and other parts
179 of the mode bits, respectively.
182 symbol ``a'' is equivalent to ``ugo''.
186 symbols represent the portions of the mode bits as follows:
188 .Bl -tag -width Ds -compact -offset indent
192 The set-user-ID-on-execution and set-group-ID-on-execution bits.
198 The execute/search bits.
200 The execute/search bits if the file is a directory or any of the
201 execute/search bits are set in the original (unmodified) mode.
204 symbol ``X'' are only meaningful in conjunction with the
206 symbol ``+'', and are ignored in all other cases.
208 The user permission bits in the original mode of the file.
210 The group permission bits in the original mode of the file.
212 The other permission bits in the original mode of the file.
217 symbols represent the operation performed, as follows:
220 If no value is supplied for
222 the ``+'' operation has no effect.
223 If no value is supplied for
225 each permission bit specified in
227 for which the corresponding bit in the file mode creation mask
229 Otherwise, the mode bits represented by the specified
235 If no value is supplied for
237 the ``\-'' operation has no effect.
238 If no value is supplied for
240 each permission bit specified in
242 for which the corresponding bit in the file mode creation mask
243 is clear, is cleared.
244 Otherwise, the mode bits represented by the specified
250 The mode bits specified by the
252 value are cleared, or, if no who value is specified, the owner, group
253 and other mode bits are cleared.
254 Then, if no value is supplied for
256 each permission bit specified in
258 for which the corresponding bit in the file mode creation mask
260 Otherwise, the mode bits represented by the specified
269 specifies one or more operations to be performed on the mode
270 bits, and each operation is applied to the mode bits in the
273 Operations upon the other permissions only (specified by the symbol
274 ``o'' by itself), in combination with the
276 symbols ``s'' or ``t'', are ignored.
278 .Bl -tag -width "u=rwx,go=u-w" -compact
280 make a file readable by anyone and writable by the owner only.
283 deny write permission to group and others.
286 set the read and write permissions to the usual defaults, but
287 retain any execute permissions that are currently set.
290 make a directory or file searchable/executable by everyone if it is
291 already searchable/executable by anyone.
296 make a file readable/executable by everyone and writable by the owner only.
299 clear all mode bits for group and others.
302 set the group bits equal to the user bits, but clear the group write bit.
307 option for the naughty bits.
311 option is non-standard and its use in scripts is not recommended.
327 utility is expected to be
329 compatible with the exception of the
333 which is not included in that standard.