An in-depth exploration of the art of shell scripting
Mendel Cooper
This tutorial assumes no previous knowledge of scripting or programming, but progresses rapidly toward an intermediate/advanced level of instruction . . . all the while sneaking in little nuggets of UNIX® wisdom and lore. It serves as a textbook, a manual for self-study, and as a reference and source of knowledge on shell scripting techniques. The exercises and heavily-commented examples invite active reader participation, under the premise that the only way to really learn scripting is to write scripts.
This book is suitable for classroom use as a general introduction to programming concepts.
Advanced Bash-Scripting Guide dyhr.com
Advanced Bash-Scripting Guide freecode.org (original)