Linux 101: What are environment variables? Your email has been sent Jack Wallen introduces you to Linux environment variables. What are they and how are they set and ...

Are you currently learning Bash? Have you seen things like $0 and $EUID and wondered what they mean? Or what the difference is between $UID and $EUID? I'll cover ...

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 ...

Ever wondered why programming in Bash is so difficult? Bash employs the same constructs as traditional programming languages; however, under the hood, the logic is rather different. The Bourne-Again ...

While Linux systems install with thousands of commands, bash also supplies a large number of “built-ins”—commands that are not sitting in the file system as separate files, but are part of bash itself ...

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 ...

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 ...

Bash, aka the Bourne-Again Shell, has a newly discovered security hole. And, for many Unix or Linux Web servers, it's a major problem. The flaw involves how Bash evaluates environment variables. With ...