my %db;
foreach my $file ( @ARGV ) {

  print "Opening $file" if DEBUG;
  
  open ( my $fh, '<', $file )
    or die "can not open $file"
  ; 
  
  while ( my $line = <$fh> ) {
    chomp $line;
    
    $line =~ tr/\0375//d;
    
    next unless $line =~ /(.*?)[.-]*\t(.*)/;
    
    my ( $k, $v ) = ( $1, $2 );
    
    $db{$k} = undef;
    
  }
  
}

print for keys %db;