If you're working in a Linux environment, chances are you've encountered environment variables—even if you didn’t realize it at the time. They quietly power much of what goes on behind the scenes in ...

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 ...

Want to know the tricks of replacing a variable in a file using the SED command? This article will give you an overview of replacing a variable value in a file using SED. Before replacing a variable ...

The eval command allows you to run the contents of variables as commands and can be very useful, especially in scripts. There are probably a lot of Linux users who have never encountered the eval ...