Security is the prime concern of linux system. The basic security of a Linux installation is based on file permissions. In this section you will learn about the file security. In RHEL Default file permission is set through the umask shell variable. We would start form default file permission. Later in this section we cover how it is tested in RHCE exam.

Managing permissions and ownership involves commands such as chmod, chown, and chgrp. Users and groups own files. SUID and SGID permissions can give all users access to specific files. Ownership is based on the default user and group IDs of the person who created a file. We would also cover them in this section.