sub remove_cruft
{
  my $line = shift;
  # do stuff to one $line here.
  $line;
}
# use as:
while (my $l = <$fh>)
{
  $l = remove_cruft($l);
  $l = remove_other_cruft($l);
  $l = remove_yet_more_cruft($l);

  # or ...
  $l = $_->($l) foreach (\&remove_cruft, \&remove_other_cruft, \&remove_yet_more_cruft);

  # or ...
  $l = remove_yet_more_cruft(remove_other_cruft(remove_cruft($l)));
  # on second thought, don't do that last one :-)

}

##</code><code>##

sub remove_cruft
{
  # do stuff to single line $_[0];
}
# use as:
while (my $l = <$fh>)
{
  remove_cruft($l);
  remove_other_cruft($l);
  remove_yet_more_cruft($l);

  # or ...
  $_->($l) foreach (\&remove_cruft, \&remove_other_cruft, \&remove_yet_more_cruft);

}