`chgrp': Change group ownership
===============================
`chgrp' changes the group ownership of each given FILE to GROUP
(which can be either a group name or a numeric group id) or to the
group of an existing reference file. Synopsis:
chgrp [OPTION]... {GROUP | --reference=REF_FILE} FILE...
The program accepts the following options. Also see Note:Common
options.
`-c'
`--changes'
Verbosely describe the action for each FILE whose group actually
changes.
`-f'
`--silent'
`--quiet'
Do not print error messages about files whose group cannot be
changed.
`--dereference'
Do not act on symbolic links themselves but rather on what they
point to.
`-h'
`--no-dereference'
Act on symbolic links themselves instead of what they point to.
This is the default. This mode relies on the `lchown' system call.
On systems that do not provide the `lchown' system call, `chgrp'
fails when a file specified on the command line is a symbolic link.
By default, no diagnostic is issued for symbolic links encountered
during a recursive traversal, but see `--verbose'.
`--reference=REF_FILE'
Change the group of each FILE to be the same as that of REF_FILE.
If REF_FILE is a symbolic link, do not use the group of the
symbolic link, but rather that of the file it refers to.
`-v'
`--verbose'
Output a diagnostic for every file processed. If a symbolic link
is encountered during a recursive traversal on a system without
the `lchown' system call, and `--no-dereference' is in effect,
then issue a diagnostic saying neither the symbolic link nor its
referent is being changed.
`-R'
`--recursive'
Recursively change the group ownership of directories and their
contents.