Managing Linux File Permissions

Description

The basic file security mechanism that we have in the Linux is the file mode or standard permissions. In this eBook we dive into the basic file mode or the Linux file permissions. Looking both at standard and special permissions that are set within the Linux file mode. The focus is purely on the file’s mode and the ownership of files, later modules will look at how we can extend the mode using ACLs, both locally and for Network File Systems.

During this module you will learn:

• Linux file permissions, read, write, execute, special permissions
• Linux file types,  regular, directories, links, pipes, sockets, block and character devices
• Reading permissions with the commands ls and stat
• Reading permissions with Perl scripts
• Octal and Symbolic notation
• File Ownership, user owner, group owner, chgrp, chown
• Default permissions and the umask
• Setting permissions with chmod
• Using chmod -v to display permissions after setting
• Permissions needed for tasks
• Special permissions
• Control deletions with the sticky bit
• Control file ownership with the SGID bit
• Console messaging and the SGID bit
• Gaining access using SUID programs