chmod command help
chmod - change file access permissions
chmod [OPTION]... MODE[,MODE]... FILE...
chmod [OPTION]... OCTAL_MODE FILE...
chmod [OPTION]... --reference=RFILE FILE...
This manual page documents the GNU version of chmod.
chmod changes the permissions of each given file according
to mode, which can be either a symbolic representation of
changes to make, or an octal number representing the bit
pattern for the new permissions.
The format of a symbolic mode is `[ugoa...][[+-=][rwxXs
tugo...]...][,...]'. Multiple symbolic operations can be
given, separated by commas.
A combination of the letters `ugoa' controls which users'
access to the file will be changed: the user who owns it
(u), other users in the file's group (g), other users not
in the file's group (o), or all users (a). If none of
these are given, the effect is as if `a' were given, but
bits that are set in the umask are not affected.
The operator `+' causes the permissions selected to be
added to the existing permissions of each file; `-' causes
them to be removed; and `=' causes them to be the only
permissions that the file has.
The letters `rwxXstugo' select the new permissions for the
affected users: read (r), write (w), execute (or access
for directories) (x), execute only if the file is a direc
tory or already has execute permission for some user (X),
set user or group ID on execution (s), save program text
on swap device (t), the permissions that the user who owns
the file currently has for it (u), the permissions that
other users in the file's group have for it (g), and the
permissions that other users not in the file's group have
for it (o).
A numeric mode is from one to four octal digits (0-7),
derived by adding up the bits with values 4, 2, and 1.
Any omitted digits are assumed to be leading zeros. The
first digit selects the set user ID (4) and set group ID
(2) and save text image (1) attributes. The second digit
selects permissions for the user who owns the file: read
(4), write (2), and execute (1); the third selects permis
sions for other users in the file's group, with the same
values; and the fourth for other users not in the file's
group, with the same values.
is not a problem since the permissions of symbolic links
are never used. However, for each symbolic link listed on
the command line, chmod changes the permissions of the
pointed-to file. In contrast, chmod ignores symbolic
links encountered during recursive directory traversals.
like verbose but report only when a change is made
-f, --silent, --quiet
suppress most error messages
output a diagnostic for every file processed
use RFILE's mode instead of MODE values
change files and directories recursively
--help display this help and exit
output version information and exit
Each MODE is one or more of the letters ugoa, one of the
symbols +-= and one or more of the letters rwxXstugo.
Report bugs to <email@example.com>.
The full documentation for chmod is maintained as a Tex
info manual. If the info and chmod programs are properly
installed at your site, the command
should give you access to the complete manual.
Comments - most recent first
(Please feel free to answer questions posted by others!)
(05 Dec 2011, 16:40
This is really help a lot. Thank you
(02 Apr 2010, 06:32
This command is good to give the permission @ edit the mode & permission.
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