Look at the int.erl and i.erl modules. Here are som useful shell commands: ii(Mod) %% Debug this Module ii(Mod, Switches), ib(Mod,Line) %% Set break point iaa(init) %% attach (bring up window) at entry of module iaa(break) %% attach (bring up window) when hitting breakpoint im() %% bring up the monitor Cheers /Tobbe