Conclusion

Permissions are vitally important for the security and even sanity of a Linux system, and they can seem overwhelming at first. With a bit of thought and learning, however, it's possible to get a good handle on Linux permissions and use them to your advantage. The combination of chgrp to change group ownership, chown to change user ownership (and group ownership as well), and the powerful chmod gives a Linux user a wealth of tools at her disposal that enable her to set permissions in a powerful, effective way.