Print Ubuntu Server IP or EC2 Public IP with Bash Script

How to get EC2 public IP from command line or bash script

Recently, while helping out with the OpenPhoto project, I created a bash script that would print out the Ubuntu server’s IP address if it was not installed on Amazon’s EC2. If it is installed on EC2 it would get the publicly accessible IP address of the machine and print that out instead.

# finding IP address and compensating for possible EC2 installation
EC2=`curl --silent --connect-timeout 1`
if [[ $EC2 != "" ]]; 
    IP=`echo $EC2 | sed -rn 's/ec2-(.*?)\.compute.*/\1/p' | sed 's/-/./g'`
    IP=`ifconfig eth0 | grep 'inet addr:' | cut -d: -f2 | awk '{ print $1}'`