"A special application called a debugger probes running code, allowing you to suspend execution arbitrarily, examine objects, explore the call stack, and even change the value of a variable on the fly. Learn how to use a debugger to squash bugs in your PHP code.
"According to popular folklore, the first computer bug was literally a bug--specifically, an ill-fated moth that landed in a relay in the Mark II Aiken Relay Calculator being tested at Harvard University. According to the operator's log entry dated 09 Sep 1947, the moth was the 'First actual case of [a] bug being found [in a computer]...'"
