Awk is a tool for processing text files, or data that is treated as text.

For some stuff I have been working on, I tend to use Awk a lot to filter down text being returned from another program (like a ls command).

Here is a nice tutorial on Awk.

Also, when using regular expressions (regexp, or regex) with Awk, here are a few helpful reminders and links.

Regexp cheat sheet.

Test regular expressions.

Regexp website (tutorials and more)

Another Regexp tutorial