temp-ip.sh

#!/bin/bash

# Programme changes IP address of the given hostname
# It expects the hostname already written in /etc/hosts e.g.
#
# 192.168.5.213  ec2.test
#
# author Marek Pietrzak
# date 04.05.2014
# licence MIT

HOSTNAME=ec2.test

if [ -z "$1" ]
  then
    echo "Usage: temp-ip [ip address]"
    exit 0
fi

echo "Changing IP address of the hostname $HOSTNAME to $1"

# safe copy of /etc/hosts
cp /etc/hosts /tmp/etc-hosts.safecopy

# change IP address
sed -i.bak "s/\([0-9\.]*\)\([^I]$HOSTNAME\)/$1\2/" /etc/hosts

# remove old entry from ~/.ssh/known_hosts
sed -i.bak "/$HOSTNAME/ d" ~/.ssh/known_hosts