some important things for me

lsb_release -a

cat /etc/lsb-release 
to learn os


adduser username
usermod -aG sudo username
su - username
to add user and switch to it




userdel mynewuser
userdel -r mynewuser
visudo
mynewuser ALL=(ALL:ALL) ALL
to delete user


ps aux and top



Command 1. Using wget
# wget http://ipecho.net/plain -O - -q ; echo


Command 2: Using curl
# curl ipecho.net/plain; echo


Command 3: Using wget
# wget http://observebox.com/ip -O - -q ; echo


Command 4: Using curl
# curl icanhazip.com


Command 5: Using curl
# curl ifconfig.me
to get public ip