Linux uses a permission model that controls which users can read, write, or execute files and directories.
Each file has: - Owner (user) - Group - Others - Permission bits (r, w, x)
- r (read): View file contents or list directory.
- w (write): Modify file or add/remove directory contents.
- x (execute): Run a file as a program or enter a directory.
rwxr-x---
- r = 4\
- w = 2\
- x = 1
Example:
rwxr-x--- = 750
chmod 755 file
chmod u+x script.sh
chown user file
chgrp dev file
Run file with owner's privileges.
Run with group's privileges or inherit group on directories.
Only owner can delete files in the directory.
Example:
chmod 1777 /tmp
ls -l
- Directories need execute (x) to be entered.
- Directories need read (r) to list contents.
- Directories need write (w) to create/delete files.