# edit sudo config file
$ sudo visudo

# running command as another user
$ sudo -u another_user whoami

# root shell
$ sudo bash

config file – what means ALL

linuxtechi ALL=(ALL) ALL 1st ALL: allow using sudo from any terminal, any machine 2nd ALL: allow using sudo to run command as other users 3rd ALL: allow using sudo to run any command as root

config file – run sudo without password

userA ALL=(ALL) NOPASSWD: ALL