chmod.1 (2010 09)

chmod(1) chmod(1)

International Code Set Support

Single- and multibyte character code sets are supported.

RETURN VALUE

Upon completion,

chmod returns one of the following values:

0 Successful completion.

>0 An error condition occurred.

EXAMPLES

Deny write permission to others:

chmod o-w ﬁle

Make a ﬁle executable by everybody:

chmod a+x ﬁle

Assign read and execute permission to everybody, and set the set-user-ID bit:

chmod a=rx,u+s ﬁle

Assign read and write permission to the ﬁle owner, and read permission to everybody else:

chmod u=rw,go=r ﬁle

or the obsolescent form:

chmod 644 ﬁle

Traverse a directory subtree making all regular ﬁles readable by user and group only, and all executables

and directories executable (searchable) by everyone:

chmod -R ug+r,o-r,a+X pathname

If the current value of

umask is 020 (umask -S displays u=rwx,g=rx,o=rwx

; do not change write

permission for group) and the current permissions for ﬁle

mytest are 444 (a=r), displayed by

ls -l as

-r--r--r--, then the command

chmod +w mytest

sets the permissions to 646 (uo=rw,g=r), displayed by ls -l as -rw-r--rw-

If the current value of

umask is 020 (umask -S displays u=rwx,g=rx,o=rwx

; do not change write

permission for group) and the current permissions for ﬁle

mytest are 666 (a=rw), displayed by

ls -l

as -rw-rw-rw-, then the command

chmod -w mytest

sets the permissions to 464 (uo=r,g=rw), displayed by ls -l as -r--rw-r--

DEPENDENCIES

The

-A option causes chmod to fail on ﬁle systems that do not support ACLs.

AUTHOR

chmod was developed by AT&T and HP.