sudo: unable to resolve host oldhostname

After changing the hostname in /etc/hostname you might get the following message when sudo'ing:

sudo: unable to resolve host oldhostname

In that case just edit the oldhostname in  /etc/hosts and the error/warning will be gone.

Installing Ion3 on Debian Squeeze

Maybe it is too obvious, but I didn't find a single instruction on it. So here is how to actually do it:

1. Since the Ion3 package isn't included in the squeeze repositories, you will have to add the repositories of oldstable i.e. lenny. Just add the following two lines to your /etc/apt/sources.list (you need to be root to edit this file):

deb ftp://de.debian.org/debian/ lenny non-free
deb-src ftp://de.debian.org/debian/ lenny non-free

Note: ftp://de.debian.org/ is the german mirror, eventually you'll want to change it to a nearby mirror of your choice.

2. Update the cache:

#apt-get update

3. Install Ion3:

#apt-get install Ion3