$ cd -
/home/jkeenan/learn/perl
$ cat abc.pl
print "hello world\n";
print "goodbye world\n";
$ perl -d abc.pl

Loading DB routines from perl5db.pl version 1.49_04
Editor support available.

Enter h or 'h h' for help, or 'man perldebug' for more help.

main::(abc.pl:1):	print "hello world\n";
  DB<1> c
hello world
goodbye world
Debugged program terminated.  Use q to quit or R to restart,
use o inhibit_exit to avoid stopping after program termination,
h q, h R or h o to get additional info.
  DB<1> q