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 ...

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 ...

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 ...

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 ...

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 ...

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 ...

I'm working on some scripts that execute on various servers, and I'm trying to consolidate them into one. The problem is that I need to run remote commands but can't ...

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 ...

Typically we interact with the Linux operating system through what is referred to as a shell interpreter. A common interpreter is the Bourne Again Shell, which people call by the catchy name of bash ...