$slot = 1;

my $pm = new Parallel::ForkManager( 2 );

foreach $key ( sort { lc $a cmp lc $b || $a cmp $b } keys %array ) {
	if( $slot == 2 ){ $slot = 1; } elsif( $slot == 1 ){ $slot = 2; }
	$pm->start and next;
	if( ! -e "/mnt/storage/videotemp/$key.hevc" ) {
		$cmd = 'WINEPREFIX=~/.wine64_'.$slot.' wine ... ;
		print "\n$cmd\n\n";
		exec($cmd);
	}
	$pm->finish;
}

$pm->wait_all_children;

##</code><code>##

@data = ( 10,4,20,2,15,6 );

%slot = ( 'one' => 'unoccupied', 'two' => 'unoccupied' );

my $pm = new Parallel::ForkManager( 2 );

DATA_LOOP:
foreach my $n (@data) {
	if ( $slot{ 'one' } eq 'unoccupied' ) { $slotnow = 'one'; $slot{ 'one' } = 'occupied'; } elsif ( $slot{ 'two' } eq 'unoccupied' ) { $slotnow = 'two'; $slot{ 'two' } = 'occupied'; }
	$pm->start and next DATA_LOOP;
	print $slotnow." sleep($n)\n";
	system( "sleep $n" );
	#print "- $slot{$slotnow} - $n\n";
	$slot{ $slotnow } = 'unoccupied';
	#print Dumper( %slot );
	$pm->finish;
}
$pm->wait_all_children;