Bash

Local IP

ifconfig

To install the application above

sudo apt-get install net-tools

Default bash arguments

MY_VAR="${1:-foo}"

Getting my public ip

dig +short myip.opendns.com @resolver1.opendns.com

Redirecting local access from port A to port B

sudo iptables -A PREROUTING -t nat -i wlp2s0 -p tcp --dport 80 -j REDIRECT --to-port 5298