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Shell Scripting (Bash) · Module 5 of 10

Permissions and processes

Manage file permissions and running programs.

📖 Key ideas

  1. ls -l shows permissions like -rwxr-xr--.
  2. chmod changes permissions: chmod +x script.sh, chmod 644 file.
  3. chown changes owner; sudo runs as admin.
  4. ps, top/htop show processes; kill PID stops one.
  5. Run in background with &; jobs, fg, bg manage jobs.
💡 Real-life example: Permissions are a house key system: owner, family (group) and visitors (others) get different keys.
chmodChanges permissions
rwxRead, write, execute
sudoRun as superuser
killSends a signal to a process