% cat .perldb sub afterinit { $DB::single = 1 } % cat debugMod.pl use LWP::UserAgent; warn "Done"; % perl -d debugMod.pl Loading DB routines from perl5db.pl version 1.33 ... main::CODE(0x43050c)(debugMod.pl:1): 1: use LWP::UserAgent; DB<1> s LWP::UserAgent::CODE(0x26c274c)(.../lib/LWP/UserAgent.pm:3): 3: use strict; DB<1> T $ = LWP::UserAgent::BEGIN() called from file `.../lib/LWP/UserAgent.pm' line 3 $ = eval {...} called from file `.../lib/LWP/UserAgent.pm' line 3 $ = require 'LWP/UserAgent.pm' called from file `debugMod.pl' line 1 $ = main::BEGIN() called from ... $ = eval {...} called from ... DB<1>