Text-Processing Commands

In the previous sections, we learned about the two main composing mechanisms of command lines: redirection and piping. In this topic, we will expand our vocabulary of commands that, when combined, let us do a wide variety of data-processing tasks.

We focus on text-processing because it applies to a wide range of real-life data, and will be useful to professionals in any field. A huge amount of data on the internet is in textual form, and text happens to be the easiest way to share data in a portable way as simple columnar CSV (comma-separated values) or TSV (tab-separated values) files. Once you learn these commands, you do not have to rely on the knowledge of any specific software GUI tool, and you can run complex tasks on the shell itself. In many cases, running a quick shell pipeline is much faster than setting up the data in a more complex GUI tool. In a later chapter, you will learn how to save your commands as a sort of automatic recipe, with shell...