Purging Old Kernels on Ubuntu
=============================

Problem
-------

Old kernel images are not automatically removed during apt-get upgrade
procedures. This can result in wasted disk space in /boot, and in some cases
can end up filling /boot and preventing further updates to the kernel. 


Solution
--------

Removing old kernels is straightforward, as shown in this excerpt from `askubuntu.com`_

Open terminal and check your current kernel::

  uname -r 

DO NOT REMOVE THIS KERNEL!

Next, type the command below to view / list all installed kernels on your
system.

::

  dpkg --list | grep linux-image 

Find all the kernels that lower than your current kernel. When you know which
kernel to remove, continue below to remove it. Run the commands below to
remove the kernel you selected.

::

  sudo apt-get purge linux-image-x.x.x.x-generic 

.. note:: 
    You can use bash's brace substitution to refer to a series of kernel
    versions. For example::
    
      sudo apt-get purge linux-image-2.6.32-4{0..5}-server

Reboot your system.

If you can't run update because the partition is full, then manually removing
one of the old images from /boot will generally free up enough space. 


.. _askubuntu.com: http://askubuntu.com/questions/2793/how-do-i-remove-or-hide-old-kernel-versions-to-clean-up-the-boot-menu
