Purge old kernel's on reboot

purge-old-kernels.sh

#!/bin/bash

dpkg --get-selections | `#show all installed packages` \
  grep 'linux-image-*' | `#select all installed images` \
  awk '{print $1}' | `#select only package name)` \
  egrep -v "linux-image-$(uname -r)|linux-image-generic" | `#remove current and base kernel from list` \
  head -n -2 | `#remove two recent kernels from list` \
  sed 's/^linux-image-\(.*\)$/\1/' |  \
  while read n
  do 
    echo 'Purging unneeded kernel images and headers for: '$n
    sudo apt-get --yes purge linux-image-$n    #purge images
    sudo apt-get --yes purge linux-headers-$n  #purge headers
  done

crontab: @reboot purge-old-kernels.sh