seek($fh, 0, 0) or die "Cannot seek to start of $json_file: $!\n";
truncate($fh, 0) or die "Cannot truncate $json_file: $!\n";
seek($fh, 0, 0) or die "Cannot seek to start of $json_file: $!\n";
truncate($fh, 0) or die "Cannot truncate $json_file: $!\n";