In this chapter, we will explore how the Linux permission scheme is implemented. Read, write, and execute permissions for files and directories will be discussed, and we will see how they affect files and directories differently. We will see how multiple users can work together using groups, and how some files and directories are available to others as well.

The following commands will be introduced in this chapter: id, touch, chmod, umask, chown, chgrp, sudo, useradd, groupadd, usermod, mkdir, and su.

The following topics will be covered in this chapter:

• Read, write, and execute
• Users, groups, and others
• Working with multiple users
• Advanced permissions