The -d command line option makes your script run under the debugger. You can either add it to the options in the #! line at the beginning of your script, or you can override the options by explicitly running the script through perl. So for example, if wombat.pl currently has the -w option set, you can either change its first line to
or you can type
% perl -wd wombat.pl
to debug it without having to change the script. Unlike some debuggers, with this one you supply arguments to the program on the command line, not as part of a debugger command; for example:
% perl -wd wombat.pl kangaroo platypus wallaby
The debugger will announce itself and provide a prompt:
Loading DB routines from perl5db.pl version 1.07 ...