Unix in a Nutshell, 4th Edition

Name

chmod

Synopsis

    chmod [options]mode files

Change the access mode of one or more files. Only the owner of a file or a privileged user may change its mode. Create mode by concatenating the characters from who, opcode, and permission. who is optional (if omitted, default is a); choose only one opcode.

Common Options

-f, --quiet, --silent

Do not print error messages about files that cannot be changed.

-R, --recursive

Recursively descend through the directory, including subdirectories and symbolic links, setting the specified group ID as it proceeds. The last of -H, -L, and -P takes effect when used with -R.

GNU/Linux and Mac OS X Option

-v, --verbose

Verbosely describe ownership changes.

GNU/Linux Options

-c, --changes

Print information about files that are changed.

--no-preserve-root

Do not treat the root directory, /, specially (the default).

--preserve-root

Do not operate recursively on /, the root directory.

--reference= filename

Change the group to that associated with filename. In this case, newgroup is not specified.

Mac OS X Options

+a, +a#, -a, =a#

Parse, order, remove or rewrite ACL entries. See the chmod(1) manpage for more information.

-C

Exit nonzero if any files have ACLs in noncanonical order.

-E

Read new ACL information from standard input. If it parses correctly, use it to replace the existing ACL information.

-H

When used with -R, if a command-line argument is a symbolic link to a directory, recursively traverse the directory.

-i

Remove the “inherited” bit from all entries in ...