Getting ready

Besides having a terminal open (and your favorite text editor, if necessary), we only need a couple of core commands: grep, tr, cut, and touch. We're assuming that the www.packtpub.com directory that we crawled through in the previous step is still available:

$ cd ~/
$ touch {a..c}.test
$ touch {A..C}[0..2].test2
$ touch Z9.test3 Z9\,test2 Z9..test2
$ touch ~/Desktop/Test.pdf