Here is a great tool for Backbone.js app’s monitoring
Here is a great quick book on command line!
“Why handle errors?”
Because as a programmer, catching errors is part of your job. You need to know when a disk write fails, a database query times out, or a web service returns zero bytes. You need to be able to react to exceptional (and not-so-exceptional) conditions, and do The Right Thing, even if The Right Thing is merely to print out that error and exit.