Superuser or Root

• Priviliged account, with username root, with unrestricted access to files and commands
• The UID of root is 0 (zero)
  • Any user with UID 0 acts like root
• Operations restricted to root only
  • Mounting and unmounting filesystems
  • Changing the root directory of a process with chroot
  • Creating device files
  • Setting the system clock
  • Changing file ownership (on BSD systems)
  • Raising or lowering resource usage limits
  • Increasing or decreasing the priority of a process
  • Setting the system's hostname
  • Configuring network interfaces
  • Shutting down the system
• Two ways to become root
  1. Log in directly as root
  2. Use the command su while logged in a non-privileged account
• Become superuser only when absolutely necessary
  • Unlimited access to everything in the system can accidently destroy the system
  • Do all your routine work in a non-privileged mode