Chgrp

chgrp is the command to change the group owner of a file or a directory.

=Syntax= chgrp [group name] [file/directory name]
 * Where [group name]] is the group you want to change the ownership to, followed by [file/directory name].

=Options= -R
 * Recursively change group owner of files/directory

=Examples= chgrp family  /usr/pictures chgrp root    /root

= Provided by =

Most (all?) Linux distributions incorporate this from the GNU Coreutils: man page

= Related Commands =
 * chown- Changes user/group ownership of a file
 * chmod - Changes the user/group permissions of a file/directory
 * ls - Lists files
 * touch - update timestamps