Command Line: Bash Scripting Workshop
This workshop teaches the basic of bash scripting.
You'll need to download Data Files for this workshop.
You can find a list of general command line resources at https://github.com/nuitrcs/bash_hpc_workshops.
Bash Guide for Beginners by Machtelt Garrels is a bash scripting book/tutorial with exercises.
Shell Scripting Tutorial for writing bash scripts.