Debugging a shell script

I have been scripting various 'programs' in bash for nearly 10 years now, so there is not much that I don't know when it comes to bash shell programming. But alas! while looking for some code snippits on how to use calc to add a decimal point to a number, I came across a very nifty tidbit on shell debugging.

sh -x script.sh

the -x switch echo's everything in the script line by line until there is an error in the script. the errors are printed out next to the line that errored out. VERY VERY useful! Instead of writing 50+ lines of scripts and spending all day debugging it, the -x does all my work for me. i have used strace to debug various applications, but I couldnt' find anything for actual shell scripts. Freaking AWESOME!