Part 4 : Permissions in Linux :

Final Structure (Blog Flow)s

0) Quick setup (optional but helpful)

• Command to view permissions: ls -l

• One sample output you will decode: -rwxr-xr--

1) Start here (why it exists)

Why Permissions Exist?

2) Foundation: who gets access (u/g/o)

User , Group And Others :

• (Optional add-on under same section) Ownership & groups:
• ls -l (owner + group columns)
• id, groups, whoami

Some basic commands of Ownership & Groups in Linux

3) Read the permission string (10 characters)

Understanding the Permission String:

• File type: -, d, l

• Split: user | group | others

4) What r / w / x actually mean

• For files: read, write, execute

• For directories (most confusing part for beginners):

Directory Permissions

5) Numeric (octal) permission system (755, 644, etc.)

Numeric Permission System :

• Add this as a quick reference:

Permission Cheat Sheet :

6) Change permissions (chmod) + practical examples

Chmod Changing Permissions :

• Main chmod explanation:

Changing Permissions with chmod

• Numeric chmod examples (can merge into main chmod section):

chmod Using Numbers

7) Ownership (chown / chgrp) — complete “who” control

Ownership

• Change owner:

Changing Owner :

• Change group:

Changing Group :

8) Interview questions / recap