The Problem When debugging Erlang applications, it is frequent that additional output is required to understand what is going on. Standard ways to do this include: adding print statement debugging with io:format/2-3 (or with ct:pal/2 in common test) turning on sys module tracing with OTP processes to show more outputs trying to attach a debugger The problem with a debugger is that it can be really difficult to properly observe what goes on in a running system with timers involved; similarly, ...
