Permissions

Learn about permission levels and modifying permissions.

0 of 8 lessons complete

Syllabus

01 File Permissions Learn how to read Linux file types and owner, group, and other permission bits.
02 Modifying Permissions Learn how to change Linux permission bits with symbolic and octal `chmod` modes.
03 Ownership Permissions Learn how to inspect and change the user and group ownership of Linux filesystem objects.
04 Umask Learn how a process umask limits the permission bits requested for newly created files and directories.
05 Setuid Learn how the set-user-ID mode bit affects executable programs and why it requires careful security review.
06 Setgid Learn how set-group-ID affects executable credentials and group inheritance in shared directories.
07 Process Permissions Learn how real, effective, and saved user IDs help Linux processes track callers and manage privilege.
08 The Sticky Bit Learn how the sticky bit protects entries in shared writable directories such as `/tmp`.

Frequently Asked Questions

What permission concepts are covered?

The course explains read, write, and execute permissions; ownership; chmod; umask; process permissions; setuid; setgid; and the sticky bit.

Do I need to understand octal permission notation?

The lessons help you connect symbolic and numeric permission forms, so you can read and modify permissions confidently.

Can changing permissions create security risks?

Yes. Overly broad permissions or misuse of special bits can expose data or privileges, so the course emphasizes understanding each change before applying it.