User and Security Management Commands: | Notion

25) `who` – Show logged-in users

Function: Displays current system users.
Syntax:
```
who
```
Lesson: Useful on shared servers.

26) `whoami` – Show current user

Function: Displays your login name.
Syntax:
```
whoami
```
Lesson: Prevents mistakes on multi-user systems.

27) `chmod` – Change permissions

Function: Controls read, write, and execute rights.

Syntax:

chmod 755 script.sh
chmod u+x script.sh

Lesson: Essential for securing files.

28) `chown` – Change ownership

Function: Assigns file ownership.
Syntax:
```
chown user:group file.txt
```
Lesson: Ensures correct user access.