Although this is first and foremost a book about text processing with Ruby, it’s also about an approach to text processing that fits in with existing tools. If you’re not particularly experienced with the Unix command line and the utilities it offers, this list might help you find the right tool for the job.
There are only 16 commands here, but together they form a considerable arsenal and—along with Ruby—will provide you with the tools you need for virtually all text processing tasks.
These commands are all part of GNU’s coreutils project and are invariably packaged with Linux distributions. Mac OS X ships with virtually all of them, and those that it doesn’t can be installed using Homebrew:
$ brew ...