use IPC::Open2;

my ($read, $write);

my $pid = open2($read, $write, 'C:/Cygwin/bin/ssh -vv -o PreferredAuthentications=publickey user@domain.com');

if ($@)
{
    print STDOUT "error";
}

print $write 'ls';

close $write;

my @lines = <$read>;

close $read;

waitpid $pid, 0;

print STDOUT "Output: @lines\n";