Book Review #6

The Linux Command Line
William E. Shotts, Jr

I've been looking for a good shell scripting book when I chance upon this book. Reading the book gives me a good understanding, not only in scripting capabilities, but also the standard Linux shell programs. Things like lp, cat, grep, and sed are explored in details. I have come to the understanding that, in fact, I need this book more than anything. In my work with Raspberry Pi, I am dealing with Linux command line every day. I'm happy to say that I have written a few significant shell scripts that do not rely on powerful scripting language such as Perl or Python. Although the resulting scripts run slower, I don't mind at all. It's the learning process that matters.

In regard to Raspberry Pi, it is a great enabler device. However, I am with the opinion that a great enabler device by itself is not enough. I have numerous books about making this project or that project with Raspberry Pi. However, in the process of making the project, I have often come into the stumbling blocks of every day occurence. How do I format SD card? How to disable the screensaver? And so on. This book not only explains all the tools you need in order to navigate the Linux shell, but also gives you the powerful bash scripting technique that you can use to whip up a quick script leveraging the various Linux shell programs.

This is just my opinion, but I think this book is a must have for all Raspberry Pi users, if not all Linux users. Highly Recommended.

Raspberry Pi Journal #29

BASH Scripting

As you may know, Python is the officially supported programming language of Raspberry Pi. What you may not know is that the Raspbian shell is bash, Born/Bourne Again Shell. Bash is a more sophisticated version of sh. There is also csh, and other flavor, if you're interested.

That's why, you frequently see "#!" shebang format for script language. That has special meaning to run the program specified and feed it the content of the file. That's right. A Python script is just a program that interprets the file's content. Pretty convenient, eh?

So, what does that have to do with bash? If you're used to Windows shell, probably not much. But if you look at the documentation for bash, man bash, you'll see that it is rather involved.

Shell scripting isn't strictly computer programming, although the nuance may be lost to inexperienced coder. If you know Perl, that language was designed to act as a glue language for various programs. So, the relationship would be bash-perl-program.

And Perl is very convenient to use. I use it a lot in the past. However, sometimes you don't need the full brunt of full-featured scripting language. bash is a viable lightweight alternative.

I'm not that good of a coder with bash. Still, it is something you should learn. There was a job description that says something like:

The applicant must know Unix shell programming, but sufficiently advanced enough to realize that it is not an achievement.

In other words, shell scripting is not a proper computer programming. It is a "convenient" tool.

Let me just point to you a nice resource that I found on the web, and I happily read it. I hope you do too.

http://tille.garrels.be/training/bash/

You need to know Linux already, but for those of you who do, this is a great resource.