Usage : trace [off|call|call_other|return|args|exec|heart_beat|apply|
obj_name|numer]
Trace is used as a debugging tool. It will print a debugging message every
time the event you specify occurs during the execution of a command that you
initiated. To get some idea what is meant by this, try
trace call_other
and then type stat <yourself>. This will show you all the functions that get
called using call_other to get the information for the command.
Examples:
trace call_other
trace return
trace off