timer

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

sub pad2($){
  my $x = shift;
  $x = "0$x" if $x < 10;
  return $x;
}

sub getIntervals($){
  my $t = shift;
  my @intervals;
  while($t > 0){
    push @intervals, $t;
    $t -= 5;
  }
  return @intervals;
}

sub main(@){
  my $time = shift() || '';
  die "Usage: $0 SECONDS\n" if @_ > 0 or $time !~ /^\d+$/;

  my $start = time;
  my @intervals = getIntervals $time;
  while(1){
    my $now = time;
    my $elapsed = $now - $start;
    if($elapsed > $time){
      last;
    }
    my $rem = $time - $elapsed;
    my $min = int($rem / 60);
    my $sec = int($rem % 60);
    my $fmt = pad2($min) . ":" . pad2($sec);
    print "$fmt\n";
    if(@intervals > 0 and $intervals[0] > $rem){
      shift @intervals;
      #system "bigtext $fmt >/dev/null 2>/dev/null";
    }
    sleep 1;
  }
  #system "bigtext", "-k";
  system "alarm", "--noterm";
}
&main(@ARGV);