Good News Everyone!
I have just released the 4th Internet edition of my book, The Linux Command Line. This new edition contains a number of refinements and modernizations. In particular, the example scripts in Part 4 have been improved to increase the robustness of string handling and to serve as better examples of modern coding practice.
You can download the new version here:
https://sourceforge.net/projects/linuxcommand/files/TLCL/17.10/TLCL-17.10.pdf/download
Be sure to download the file named TLCL-17.10.pdf
Enjoy!