This post follows up on Part 1 by examining the many ways that you can test the value of variables – e.g., whether they equal particular strings like “yes” or “no”, if they have a numeric value, if ...

Variables often look like $var, but they also look like $1, $*, $? and $$. Let's take a look at what all these $ values can tell you. A lot of important values are ...

Few aspects of Unix system administration are more intimate than the relationship between the admin and their chosen shell. After all, the shell is the most fundamental interface to the system, the ...

Bash scripts are powerful, but with power comes great responsibility. It’s very easy for sloppy or poorly-planned code to do real damage, so it’s a good idea to be careful and practice defensive ...

It is easy to dismiss bash — the typical Linux shell program — as just a command prompt that allows scripting. Bash, however, is a full-blown programming language. I wouldn’t presume to tell you that ...

In our first tutorial on command line wizardry, we covered simple redirection and the basics of sed, awk, and grep. Today, we’re going to introduce the concepts of simple variable substitution and ...

One of the common tasks you'll encounter when scripting in Bash is performing arithmetic operations on variables, particularly division. This process might seem straightforward, but it requires ...

Exploring data, one index at a time.