[conspire] How do I determine what I need to keep from my internal hard drive and what is the recommend way to move things to an external hard drive

[Rick Moen]

Quoting Darlene Wallach (freepalestin at dslextreme.com):

> So how do I determine what to save off/keep/backup/image from my
> internal hard drive? And what is the recommended way to save the stuff
> off?

You're not going to want to hear this, but:  The time to think about
where the parts of your system reside that merit backup is long before
you find yourself in urgent need to back things up.

That having been said, have a look at 'Backup Scheme' on
http://linuxmafia.com/kb/Admin , for the approximate regimen I use for
the linuxmafia.com server.  Of course, it includes subtrees that almost
certainly don't exist on your non-server box, but you can ignore those.

'Copying Directory Trees' on http://linuxmafia.com/kb/Admin is useful
for figuring out how to copy files, and a general recommendation of

  rsync -avx olddirectory newdirectory

is probably all you need.

> I already moved all the data files onto my external hard drive.

Well, the first link cited includes an emphasis on making sure you've
snagged _all_ the data files, including the trees you might forget, like
/root, /var/mail AKA /var/spool/mail, and /usr/local (but it's indeed
possibly you've used nothing but /home for locally generated data
files).

The other stuff you need are:

1.  A reference snapshot of the current contents of /etc.
2.  Snapshot of your partition layout.
3.  Listing of your installed package names.

The 'Backup Scheme' page gives a Debian-centric approach to those 
problems, but you can adapt it to other systems.