use Term::ReadLine;
my $tty='/dev/pts/5';

open my $out,'>',$tty;
open my $in,'<',$tty;


my $term = Term::ReadLine->new('Simple Perl calc',$in,$out);
my $prompt = "Enter code: ";
my $OUT = $term->OUT || \*STDOUT;
while ( $_ = $term->readline($prompt) ) {
  my $res = eval($_);
  warn $@ if $@;
  print $OUT $res, "\n" unless $@;
  $term->addhistory($_) if /\S/;
}

##</code><code>##

> ls -l /proc/31965/fd/
insgesamt 0
lrwx------ 1 lanx lanx 64 Dez  1 17:18 0 -> /dev/pts/5
lrwx------ 1 lanx lanx 64 Dez  1 17:18 1 -> /dev/pts/5
lrwx------ 1 lanx lanx 64 Dez  1 17:18 2 -> /dev/pts/5