Root filesystem clean up procedure

Extracted from Fermin's message [1 https://lists.dit.upm.es/pipermail/vnuml-devel/2006-June/000411.html]

This is a description of the general procudure carried out to clean up a root_fs after upgrading/installing new packages. This is more or less what I do when generating a new root_fs release (for example, 0.3.99 based on previous 0.3.3). I'm sending to the list in the hope it could be useful for developers working in their own "root filesystem branches" based on root_fs provide by VNUML Project.

In order to clean the filesystem two steps should be performed, in sequence:

1. "Inside" filesystem (I mean, using a running virtual machine that uses this filesystem as <fylesystem type="direct"> or mounting it and chrooting from host):

- Clean the APT cache (after apt-get update, install, upgrade, etc. or whatever other APT operation)

    apt-get clean

- It is not exactly a clean up operation, but if the /lib/tls directory exists (it seems to be created sometimes during the upgrading of some packages) rename it to /lib/tls.disabled (removing previous existing /lib/tls.disabled directory) (*)

- It is not exactly a clean up operation, but you should also edit and change the /etc/root_fs_tutorial-version file (*)

2. "Outside" filesystem, supposing is mounted in /mnt/loop

  cd /mnt/loop/var/cache/apt
  rm -f pkgcache.bin srcpkgcache.bin (**)
  cd /mnt/loop/tmp
  rm -rf *
  rm -f /mnt/loop/root/.bash_history
  cd /mnt
  umount /mnt/loop

(*) This step also can be done from "outside" filesystem

(**) And, in general, any other file, except the archive/ directory