This is an issue that has been (de)bugging me lately. There are times when I have to use the Perl debugger to step through code to see where things go awry. I need to step through the code, going down into the subroutines if necessary, so I use the s command. Sure enough, I pick up a little speed and hit s on a step that has a call to some outside module, such as File::Find. I suddenly find myself outside of the code I am interested in, deep inside the File::Find module. I can hit the r to return, but I sometimes take a wrong turn there and end up coming to, groggy, in some unknown city.

My question is this: is there some way (other than driving slowly so that I can use the n judiciously) to step through code in the debugger, digging down into subroutines if needed, without fear of accidentally stepping into some use'd module? (And no, I cannot use any outside tools. Just Perl and what comes with it.)