Hello revdiablo,

Thanks for the reply. That helped understand so many things better. I changed all the things you suggested, but it still seems that the program does not enter the while loop. I even changed the hash code as you suggested, but that did not seem to be the problem. What do you advice?

Thanks.

use IO::Select; 

my %pids; 
my $s = IO::Select->new(); 

my @proc = (qw(C W)); 

for ( @proc ) { 
    my $pid = open my $fh, "dir $_: |" 
        or warn "Could not fork&open $cmd: $!" 
        and next; 
        
   print "opened $_ \n\n"; 

    $pids{$fh} = [ $pid, $_ ]; 
    $s->add($fh); 
} 

while (my @ready = $s->can_read) { 
    print "entered while loop \n\n"; 
    for my $fh (@ready) { 
        if (eof $fh) { 
            delete $pids{$fh}; 
            $s->remove($fh); 
            next; 
        } 

        my $line = <$fh>;  
        if ($line =~ /Windows/) { 
            chomp $line; 
            print "Found 'Windows' in '$line' from $pids{$fh}[1]\n"; 
            kill 15, map { $_->[0]} values %pids; 
        } 
    } 
}
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