Safely adding unstable to a stable/etch sources.list

[Chris Jones <cjns1989@gmail.com>]

I am in the process of installing live-helper on etch.

The manual tells me that I need to do the following:

  . add the unstable sources to /etc/apt/sources.list

  . do an "apt-get update"

  . install debootstrap or cdebootstrap from unstable:

    # apt-get install -t etch-backports debootstrap

  . install live-helper

    # apt-get install -t unstable live-helper

I now have this in /etc/apt/sources.list:

-------------------- /etc/apt/sources.list --------------------------
deb http://ftp.us.debian.org/debian/ stable main non-free contrib 
deb-src http://ftp.us.debian.org/debian/ stable main non-free contrib 
deb http://security.debian.org/ stable/updates main contrib

deb http://www.backports.org/debian etch-backports main

deb http://ftp.us.debian.org/debian/ unstable main non-free contrib 
deb-src http://ftp.us.debian.org/debian/ unstable main non-free contrib 
deb http://security.debian.org/ unstable/updates main contrib
-------------------- /etc/apt/sources.list --------------------------

As you can see I added the backports repository & I duplicated the first
three lines, changing stable to unstable.

Before I take the plunge, I would like to make sure I got this right ..
and in particular that the "apt-get update" is not going to screw up my
apt system. 

Also, what's the difference between debootstrap and cdebootstrap?

I do have current & functional backups.

Thanks!

CJ