Without argument, print the list of available commands. With a command name as argument, print help about that command. w(here): Print a stack trace, with the most recent frame at the bottom. An arrow indicates the “current frame”, which determines the context of most commands.d(own): Move the current frame one level down in the stack trace (to a newer frame).u(p): Move the current frame one level up in the stack trace (to an older frame).b(reak): [ ([filename:]lineno | function) [, condition] ]
With a filename:line number argument, set a break there. If filename is omitted, use the current file. With a function name, set a break at the first executable line of that function. Without argument, list all breaks. Each breakpoint is assigned a number to which all the other breakpoint commands refer.
The condition argument, if present, is a string which must evaluate to true in order for the breakpoint to be honored. tbreak: [ ([filename:]lineno | function) [, cond…