CHMOD(1)CHMOD(1)NAMEchmod - change mode
SYNOPSISchmod [ -Rf ] mode file ...
DESCRIPTION
The mode of each named file is changed according to mode, which may be
absolute or symbolic. An absolute mode is an octal number constructed
from the OR of the following modes:
4000 set user ID on execution
2000 set group ID on execution
1000 sticky bit, see chmod(2)
0400 read by owner
0200 write by owner
0100 execute (search in directory) by owner
0070 read, write, execute (search) by group
0007 read, write, execute (search) by others
A symbolic mode has the form:
[who] op permission [op permission] ...
The who part is a combination of the letters u (for user's
permissions), g (group) and o (other). The letter a stands for all, or
ugo. If who is omitted, the default is a but the setting of the file
creation mask (see umask(2)) is taken into account.
Op can be + to add permission to the file's mode, - to take away
permission and = to assign permission absolutely (all other bits will
be reset).
Permission is any combination of the letters r (read), w (write), x
(execute), X (set execute only if file is a directory or some other
execute bit is set), s (set owner or group id) and t (save text -
sticky). Letters u, g, or o indicate that permission is to be taken
from the current mode. Omitting permission is only useful with = to
take away all permissions.
When the -R option is given, chmod recursively descends its directory
arguments setting the mode for each file as described above. When
symbolic links are encountered, their mode is not changed and they are
not traversed.
If the -f option is given, chmod will not complain if it fails to
change the mode on a file.
EXAMPLES
The first example denies write permission to others, the second makes a
file executable by all if it is executable by anyone:
chmod o-w file
chmod +X file
Multiple symbolic modes separated by commas may be given. Operations
are performed in the order specified. The letter s is only useful with
u or g.
Only the owner of a file (or the super-user) may change its mode.
SEE ALSOls(1), chmod(2), stat(2), umask(2), chown(8)7th Edition May 22, 1986 CHMOD(1)
