system('/usr/bin/open', '-a', 'Preview', $postscript_file_name);

{
  open my $pipe, '|-', '/usr/bin/open', '-a', 'Preview', '-f' or die "Unable to connecto to Preview: $!\n";
  print $pipe '... some PDF, PS or other image data ...';
  close $pipe or die "Error sending data to Preview: $!\n";
}

main->_print_pod_unix("/usr/local/lib/perl5/5.8.8/pod/perl.pod");

sub _print_pod_unix {
    my($w, $path) = @_;
    if (is_in_path("pod2man") && is_in_path("groff")) {
	my $pod2ps_pipe = "pod2man $path | groff -man -Tps";

	if ($^O eq 'darwin') {
	    my $cmd = "$pod2ps_pipe | /usr/bin/open -a Preview -f";
	    system($cmd) == 0
		or $w->_die_dialog("Error while executing <$cmd>. Status code is $?");
	    return 1;
	}

	# XXX maybe determine user's environment (GNOME vs. KDE vs. plain X11)?
	my $gv = is_in_path("gv")
	      || is_in_path("ghostview")
	      || is_in_path("ggv")         # newer versions seem to work
	      || is_in_path("kghostview");
	if ($gv) {
	    #	    $w->_need_File_Temp;
	    use File::Temp;

	    my($fh,$fname) = File::Temp::tempfile(SUFFIX => ".ps");
	    system("$pod2ps_pipe > $fname");
	    push @tempfiles, $fname;
	    my $pid = fork;
	    if (!defined $pid) {
		die "Can't fork: $!";
	    }
	    if ($pid == 0) {
		exec($gv, $fname);
		warn "Exec of $gv $fname failed: $!";
		CORE::exit(1);
	    }
	    push @gv_pids, $pid;
	    return 1;
	}
    }
    return 0;
}

sub is_in_path {
    my($prog) = @_;
    require Config;
    my $sep = $Config::Config{'path_sep'} || ':';
    foreach (split(/$sep/o, $ENV{PATH})) {
	if ($^O eq 'MSWin32') {
	    return "$_\\$prog"
		if (-x "$_\\$prog.bat" ||
		    -x "$_\\$prog.com" ||
		    -x "$_\\$prog.exe" ||
		    -x "$_\\$prog.cmd"
		   );
	} else {
	    return "$_/$prog" if (-x "$_/$prog" && !-d "$_/$prog");
	}
    }
    undef;
}