my %ttys;
for $line (`aml_read /l trace /h $_[3] /a commproc /s $_[1]  /b $_[2] /d all`) {
 # I'm making this split up, you'll have to post the
 # format of aml_read or figure out the split yourself
 my ($something, $tty, $stuff) = split " ", $line;
 $ttys{$tty}++;
}

for my $tty (sort { $a <=> $b} keys %ttys) {
 print "Count for $tty: $ttys{$_}\n";
}