while (defined ( my $line = <INPUT>) ) {

##</code><code>##

while ($line = <INPUT>) {

##</code><code>##

sub parseDown {
  my $filename = shift @_; # or $_[0] or just plain shift
  # rest of sub
}

##</code><code>##

if (my ($tmp_dir, $file) = $line =~ m%(.*)\\(.*)% ) {
    # do the rest of the stuff
} else {
    warn "$line has incorrect format!\n";
}