Finally I have bought an UPS. Its the MGE Pulsar Ellipse 1200. I have chosen MGE because of their support to the open source community (mge opensource). You can connect up to four standard computers to this UPS, it’s perfect for my home network.

What I want to do is to be able to shut down [...]

We need three files for this:

signature.txt: you should point your mail client to this one
signature.tpl: here is the common text to display, something like “xmms is now playing:“
signature.sh: the script first copies the contents of the template file to the final signature file, and then adds the current song as a new line.