sub launch {
    my ($pid_file,@process_and_args) = @_;
    open my $fh, '>', $pid_file # or print to STDOUT for easier handling by ssh?
       or die "Couldn't create '$pid_file': $!";
    print {$fh} $$;
    exec(@process_and_args)
        or die "Couldn't launch [@process_and_args]: $!";
};