Jack Wallen introduces you to Linux environment variables. What are they and how are they set and unset? How many times have you installed something on Linux, only to find out that you need to set ...

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 ...

Editor's Note: This article has been updated by its author. Thank you, Pat. Have you ever wanted to change the names of many files at once? Or, have you ever needed to use a default value for a ...

What looks simple on Windows quietly turns into hours of troubleshooting.