Shell scripts can make life a lot easier. If you have never written them, and have to do a lot of repetitive work, this appendix is for you. It will give you a small tour through creating and using them, but for a more complete coverage proper literature is recommended.C.1In the second part of this appendix we will introduce you to an advanced usage of shell script, to make them look more like real NEMO programs with a ``keyword=value'' type interface.