Just playing along with: http://rebekahgolden.com/2014/01/04/art-of-computer-programming-euclids-algorithm/

microEuclid.pl

#!/usr/bin/perl
use strict;
use warnings;

print qq{Euclid's Algorithm 1.1E\n\n};

sub littleEuclid {
  my ($m,$n) = @_;
  my $remainder = $m % $n;
  my $reply = $remainder
            ? q{Nope. Reduce. (Here Knuth says in mathematical notation set m to what n is and n to what the remainder is.)}
            : qq{Yes! The remainder is zero! n is the answer! The answer is $n};
  # use a single heredoc to do all of the printing
  print <<END;
Given two numbers m = $m and n = $n, find the greatist common divisor.
Find the remainder using the modulus function (%).
The remainder is $remainder
Is the remainder zero?
$reply

END
  # recurse unless the remainder is zero
  littleEuclid($n,$remainder) if $remainder;
}

sub microEuclid {
  my ($m,$n) = @_;
  return $m % $n
       ? microEuclid($n, $m % $n)
       : $n
}


push @ARGV, 125, 15;
# pass the first two elements from @ARGV to our function
printf qq{The largest remainder of %d and %d is %d.\n}
     , $ARGV[0]
     , $ARGV[1]
     , microEuclid(splice @ARGV, 0, 2);