Shell Scripting: An Introduction to the Shift Method and Custom Functions


In Getting started with shell scripting, I covered the basics of shell scripting by creating a pretty handy “despacer” script to remove bothersome spaces from file names. Now I’ll expand that idea to an application that can swap out other characters, too. This introduces the shift method of parsing options as well as creating custom functions.

This article is valid for the bashksh, and zsh shells. Most principles in it hold true for tcsh, but there are significant differences in tcsh syntax and flow of logic that it deserves its own article. If you’re using tcsh and want to adapt this lesson for yourself, go study function hacks (tcsh hacks) and the syntax of conditional statements, and then give it a go. Bonus points shall be rewarded.