chgrp — Change the group ownership.
Summary :
chgrp changes the group ownership of each given file(s) to the specified group (group name or a numeric group id).
Examples :
$ chgrp grp1 file1 — Change the group ownership to grp1. No change in the user ownership.
$ chgrp grp1 f1 f2 f3 — Same as above, but for files f1, f2 and f3.
$ chgrp 400 file1 — Change the group ownership to a group, GID:400.
$ chgrp -R grp1 dir1 — Recursively change group ownership of Dir and their contents.
$ chgrp -c grp1 f1 f2 f3 — Show verbose output only when a change is made.
$ chgrp -v grp1 f1 f2 f3 — Show verbose output for every file processed.
$ chgrp -f grp1 f1 f2 f3 — Force/Silent/Quiet. Do not print error messages.
$ chgrp –reference=that this — Set the ‘that’ file’s group to ‘this’.
Note: Instead of Group name, Group ID can be used.
$ echo $GROUPS — Show Group ID.
Read : man chgrp