Macintosh Terminal Pocket Guide

Group Management

groups	Print the group membership of a user.
dscl	Create, modify, and delete groups.

A group is a set of accounts treated as a single entity. If you give permission for a group to take some action (such as modify a file), then all members of that group can take it. For example, you can give full permissions for the group friends to read, write, and execute the file /tmp/sample:

➜ groups
users smith friends
➜ chgrp friends /tmp/sample
➜ chmod 770 /tmp/sample
➜ ls -l /tmp/sample
-rwxrwx---  1 smith friends  2874 Oct 20 22:35 /tmp/sample

To add users to a group, use dscl. To change the group ownership of a file, recall the chgrp commands from File Properties.