..which makes the returned handle a pipe of the output of the program.

Ie the output of the default program associated (in the registry) to the .txt file extension.
The ikegami suggestion assume that you want open a file for reading, as you shows in you code; the read mode is the default when opening files, with or without IO::File. Anyway i think is preferable to specify always the mode:

  $file=IO::File->new('c:/scripts/002.txt');
  # is the same of
  $file=IO::File->new('c:/scripts/002.txt','<');

  #as

  open my $fh,       'c:/scripts/002.txt' or die "unable to open a fil
+e to read";
  # equal to
  open my $fh, '<',  'c:/scripts/002.txt' or die "unable to open a fil
+e to read";
[download]

As final tip see how i specified the path: even if untold you can always and safely use the same path separtor you would use in Linux with the benefit of less keystroke and perhaps a bit of portability more.

UPDATE: as for searching the line number take a look to $. described in perlvar
HtH
L*