Additionally you can find my video courses on Pluralsight: http://pluralsight.com/training/Autho... and take time to see my own site http://www.theurbanpenguin.com in this video we can address some real issues to help you understand the objectives and put them to use. The cat command and od command may seem quite dry. But when we have a script that does not work we can use cat and od to fault find and tr to fix.