use strict;

# Do lots of stuff

write_file();

sub write_file {

  if (defined (my $pid=fork)) {
    if ($pid) { 
      # Parent, let's just continue
      return;
    } else {
      # Child, do the file mod stuff.
      do_write_file();
      exit 0;
    }
  } else {
  die "Blerch: could not fork: $!\n";
  }