open PRIMES, $primefile;
while(<PRIMES>) {
push (@parray, $_);
}
close PRIMES;

# could be 
open PRIMES, $primefile;
@parray = <PRIMES>;
close PRIMES;

##</code><code>##

if($lowrange % 2 == 0) { $lowrange++; }

# could be 

$lowrange++ unless ($lowrange % 2);

##</code><code>##

print "\nTotal amount of primes: $counter \n";
print "Your results have been saved, starting with
".$path.$beginloc.$last."\n\n";

##</code><code>##

print "\nTotal amount of primes: $counter \n",
      "Your results have been saved, starting with
".$path.$beginloc.$last."\n\n";

##</code><code>##

print "Your results have been saved, starting with
".$path.$beginloc.$last."\n\n";

# becomes
print "Your results have been saved, starting with ${path}${beginloc}${last}\n\n";