Sed

Sed can filter files to append, delete, modify and re-organise lines. It can also substitute strings amongst other features.

It uses regular expressions to process commands. If you don't know what regexps are start learning they are extremely powerful and fun.

In the following examples I will take you through some handy uses for sed.

Usage for sed is

 sed [OPTION]... {script-only-if-no-other-script} [input-file]