  $in_name = $ARGV[0] ;
  $tmp_name = $in_name . ".new" ;
  $bak_name = $in_name . ".bak" ;
  open ( in, "<$in_name" ) || die "cannot open input file $in_name" ;
  open ( out, ">$tmp_name" ) || die "cannot open output file $tmp_name" ;

  binmode ( in ) ;
  binmode ( out ) ;

  print $in_name ;
  
  while ( <in> )
    {
      if ( length == 0 or substr ( $_, 0, 1 ) ne '/' )
        {
          print out;
          next ;
        } ;
      @entry = split ( '/' ) ;
      if ( substr ( $entry[3], 8, 1 ) eq '0' )
        {
          substr ( $entry[3], 8, 1 ) = ' ' ;
        }
      $line = join ( '/', @entry ) ;
      print out $line ;
    }

  close ( in ) ;
  close ( out ) ;
  
  @s1 = stat( $in_name );
  @s2 = stat( $tmp_name );
  if ( $s1[7] != $s2[7] )
    {
      die "error. file sizes differ. changes was not saved" ;
    }

  rename ( $in_name, $bak_name ) || die "cannot rename $in_name to $bak_name" ;
  rename ( $tmp_name, $in_name ) || die "cannot rename $tmp_name to $in_name" ;

  print " ok.\n" ;

  exit 0;