If you are an infrequent ‘nix head like me, can still cobble up complex batch files from scratch, but just can’t remember stupid bash commands, here is a treat for you. FREE! I like free.
The Advanced Bash Scripting Guide is both a reference and a tutorial on shell scripting. This comprehensive book (equivalent to 974 printed pages) covers almost every aspect of shell scripting. It contains 364 profusely commented illustrative examples, a number of tables, and a cross-linked index/glossary. Not just a shell scripting tutorial, this book also provides an introduction to basic programming techniques, such as sorting and recursion. It is well suited for either individual study or classroom use. It covers Bash, up to and including version 4.0.
This release features a minor reorganization of the material. The “Indirect References” subsection is broken out as a separate chapter. Two sections of the “Variables Revisited” chapter are now in a stand-alone chapter. There is also the usual round of bugfixes and stylistic changes.