cmd line ip checker

ip

#!/bin/bash

# handy script to check your laptop's ip

if ! which ip &>/dev/null; then
    function ip {
        local addr='\d{1,3}(\.\d{1,3}){3}'

        # if the argumetn was '-' echo the external ip
        if [ "$1" = '-' ]; then
            curl http://checkip.dyndns.org/ 2>/dev/null | \
                ack -o '(?<=Address: )'$addr

        # otherwise if a hostname was given as an argument...
        elif [ "$1" ]; then

            # ...echo the corresponding ip if it's in /etc/hosts, otherwise nslookup
            ack -o $addr'(?=\s*'$1'\s*$)' /etc/hosts || \
            nslookup $1 | ack -m 2 '^Address:' | tail -1 | ack -o $addr

        # otherwise if no argument was given...
        else

            # ...echo the this machine's ip of the ethernet or the wireless
            ifconfig en0 | ack -o '(?<=inet )'$addr || \
            ifconfig en1 | ack -o '(?<=inet )'$addr
        fi
    }
fi

check that ip!!

this is a handy way to get your ip from the cmd line

get the ip of your ethernet if it's available, otherwise your wireless

$ ip

get your external ip (the IP address that websites see when you visit)

$ ip -

get the ip of some host by checking first your /etc/hosts file and then DNS

$ ip hostname.example.com

want to snatch it up in your clip board?! no sweat!

$ ip | pbcopy        # or something like clip on linux

note that it's wrapped in a check to only define itself if an ip command doesn't currently exist. get fancy and put it in a file on your $PATH or just copy and paste it into your .bashrc like a baller.