use strict;
use warnings;

sub Last_N_Lines
{
   my($String, $N) = @_;

   my @Lines = split(/\n/,  $String);
   if(scalar(@Lines) > $N)
      {
      splice(@Lines, 0, scalar(@Lines) - $N);
      }

   return(join("\n",  @Lines))
}

my $String = "This is line 1
This is Line 2
This is Line 3
This is Line 4
This is Line 5
This is Line 6
This is Line 7
This is Line 8
This is Line 9
This is Line 10";

print("Last\[5\] Lines.\[\n" . Last_N_Lines($tring, 5) . "\]\n");

##</code><code>##

Last[5] Lines.[
This is Line 6
This is Line 7
This is Line 8
This is Line 9
This is Line 10]