I just created a group. How do i make the groups read only to a specific file systems.(home directory).
You would set the group as the 'group' of the directory and set the permissions
ls -l /export/mydir
drwxrwxr-x 2 root mygrp 4096 Sep 22 2000 mydir
chmod 745 mydir
(This would change it to read only for the group, not for the world)
ls -l /export/mydir
drwxr--r-x 2 root mygrp 4096 Sep 22 2000 mydir
You may have to change the default umask (check the man page on this and all commands before doing them)
Do I need to be root to do this. I'm assuming that I do. But we know what happens when you assume:)
If you are the owner of the directory then no, you don't need to be root. To change the umask for all users, yes.
Read the man pages on the commands.