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 ...

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 ...

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 ...

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 ...

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 ...

We often read (including in the book Advanced Bash-Scripting Guide by Mendel Cooper) that if we pass variable names as parameters to functions, they will be treated as string literals and cannot be ...

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 ...

Skip one-click backup apps. This rsync script gives you full control over what gets saved and when, plus logs and a few hard-won lessons.