whoami - This is used get who is the current user. hostname – This is used to get name of the machine. who -Show who is logged into the system. Date - Show the current date and time printenv - Print vales o fall environment variables. env -Print current environment. su -T his command is used to change the shell user. su - {change the shell to the super user / root} su - root {change the shell to the super user / root} su - Saman {change the shell to the super Saman} id - This is used to print user's information id {show current user information} id Saman {show user Saman information} uname - This used to get machine and operating system information uname {show operating system} uname -a {show all info, OS, Kernel version, architecture} uname -r {show kernel version} groups - T his us...