#!/usr/bin/perl -w
#
#  Example of getting a single, non-blocking character in Linux.
#
#  060306 liverpole
#

# Strict
use strict;
use warnings;

# Create a subroutine (closure) for capturing a key
sub one_key {
    chomp(my $stty = `stty -g`);                # Save 'cooked' mode tty
    `stty -icrnl -icanon -echo min 0 time 0`;   # Begin raw mode
    sub {                                       # Create a closure
        if (!$_[0]) {                           # If argument is zero ...
            system("stty $stty");               #   restore 'cooked' mode
        } else {                                # Otherwise get and return
            `dd bs=1 count=1 <&0 2>/dev/null`;  #   a single keystroke
        }
    };
}


# Main program
my $p_one_key = one_key();
while (1) {
    print ' ' x int(rand(20)), "*\n";
    select(undef, undef, undef, 0.1);
    last if $p_one_key->(1);
}
$p_one_key->(0);