> perl -dw prog.pl

Loading DB routines from perl5db.pl

Enter h or `h h' for help.

main::(prog.pl:3):	my $firstline;

  DB<1> c 123

main::(prog.pl:123):	%hololoh # has just been loaded w/ first values

  DB<1> x %hololoh

0  HASH(0x3e5e54)
...