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 ...

String interpolation is a technique that enables you to insert expression values into literal strings. It is also known as variable substitution, variable interpolation, or variable expansion. It is a ...