Chris Johnson 
Pro Bash Programming [PDF ebook] 
Scripting the Linux Shell

Hello, World! Your First Shell Program.- Input, Output, and Throughput.- Looping and Branching.- Command-Line Parsing and Expansion.- Parameters and Variables.- Shell Functions.- String Manipulation.- File Operations and Commands.- Reserved Words and Builtin Commands.- Writing Bug-Free Scripts and Debugging the Rest.- Programming for the Command Line.- Runtime Configuration.- Data Processing.- Scripting the Screen.- Entry-Level Programming.

Chris F.A. Johnson was introduced to Unix in 1990 and learned shell scripting because there was no C compiler on the system. His first major project was a menu-driven, user-extensible database system with report generator. Chris uses the shell as his primary, general-purpose programming language, and his projects have included a member database, menuing system, and POP3 mail filtering and retrieval. Chris is the author of Shell Scripting Recipes: A Problem-Solution Approach (Apress, 2005). When not pushing shell scripting to the limit, he designs and codes web sites, teaches chess, and composes cryptic crosswords.