Manual Pages  — CHGRP

The following options are available:

-H
	If the -R option is specified, symbolic links on the command line are followed and hence unaffected by the command. (Symbolic links encountered during traversal are not followed.)
-L
	If the -R option is specified, all symbolic links are followed.
-P
	If the -R option is specified, no symbolic links are followed. This is the default.
-R
	Change the group ID of the file hierarchies rooted in the files, instead of just the files themselves. Beware of unintentionally matching the " .." hard link to the parent directory when using wildcards like ".*".
-f
	The force option ignores errors, except for usage errors and does not query about strange modes (unless the user does not have proper permissions).
-h
	If the file is a symbolic link, the group ID of the link itself is changed rather than the file that is pointed to.
-v
	Cause chgrp to be verbose, showing files as the group is modified. If the -v flag is specified more than once, chgrp will print the filename, followed by the old and new numeric group ID.
-x
	File system mount points are not traversed.

The -H, -L and -P options are ignored unless the -R option is specified. In addition, these options override each other and the command's actions are determined by the last one specified.

The group operand can be either a group name from the group database, or a numeric group ID. If a group name is also a numeric group ID, the operand is used as a group name.

The user invoking chgrp must belong to the specified group and be the owner of the file, or be the super-user.