This is the dark magic section of the chapter. It will demonstrate advanced shell scripting by taking the preceding lessons and features, and converting them into what could be considered a small program.
Advanced shell scripting magic
Here be dragons, ye be warned
A simple piece of introductory code is great to get a feel for the flavor of a language, but we're going to introduce some dark magic in the form of some complex utility functions that can be helpful in everyday situations. We'll use a lineinfile function to insert arbitrary text into a file—it's not a full-featured application, just enough to help ensure some simple text is injected into a file. The second function, ncz, leverages bash IP...