Here are a couple of examples, including a Tk example. GUI's will not need Term::Readkey and the cumbersome while(1) loop.

#!/usr/bin/perl
use Term::ReadKey;
#passing ReadKey() an argument of -1 to indicate not to block: 
ReadMode('cbreak');

while(1){
my $char;
if (defined ($char = ReadKey(0)) ) {
        print "$char->", ord($char),"\n";    # input was waiting and i
+t was $char 
} else {
          # no input was waiting 
        }
}

ReadMode('normal');   # restore normal tty settings
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#!/usr/bin/perl
use warnings;
use strict;
use Tk;

my $down = 0;
my $mw = MainWindow->new;
$mw->bind("<Key>",  sub { &pressed  } );
$mw->bind("<KeyRelease>",  sub { &released  } );
MainLoop;

sub pressed{
  my($widget) = @_;
  my $e = $widget->XEvent;    # get reference to X11 event structure 
  my $binding = 'Character = ' . $e->N . ', keysym = ' . $e->K . '.';
  print "$binding\n";
  print $e->K," pressed\n";
}


sub released{
  my($widget) = @_;
  my $e = $widget->XEvent;    # get reference to X11 event structure 
  my $binding = 'Character = ' . $e->N . ', keysym = ' . $e->K . '.';
  print "$binding\n";
  print $e->K," released\n";
}
[download]