For anyone who is new to the Unix world, Linux Magazine is running a series of articles on learning shell scripting. Part one introduces the basics, while part two introduces while loops.
It's not widely known that bash has its own debugger - possibly because most Linux distributions don't install it by default. Linux.com show how to install it, and show a number of examples of using it to debug your own scripts.
Mitch Frazier explains how to make use of parentheses to execute groups of commands in the background within shell scripts, in his Linux Journal article on subshells.
Linux Journal has published another article in its series on Bourne-again shell programming for beginners, this time with a tutorial on redirecting input from multiple files.
When I hear the phrase "floating point math", the idea of performing it within a shell programming language is probably the furthest from my mind. Nevertheless, the people at Linux Journal have managed to print a two-part article on this very topic: