system administration

In order to install, update or configure a system you need special privileges, which a 'normal' user does not need.

These privileges are called super user privileges or root privileges. There are several methods to gain super user privileges. Each of them has its up and downsides.

  • super user / root account
  • login / su / sudo
  • /etc/securetty
  • /etc/shells
  • chmod / umask
  • chown / chgrp
  • /etc/shells
  • system calls

Login

Console login as root user

login: root
Password:
Last login: Thu May 17 13:35:10 EDT 2018 from 192.168.175.45 on pts/0
...
  • Avoid logging in as root user
  • system can be configured to deny root logins
    • /etc/securetty (list of terminals on which root is allowed to login)

su / sudo ( open root shell )

sh$ su
Password:
sh#
sh$ sudo -i
Password:
sh#

execute with super user privileges

sh$ sudo apt update
Password:
...
sh$