This script prints STDIN, or lines of files which are ARGS. I have a situation that slow print down to STDOUT to see what were print. I saw these lines to check does it almost good. But some times, STDOUT is too fast to see it, thus, this script slows STDOUT down.

slowcat

#!/usr/bin/perl -s
use utf8;
use strict;
use warnings;
use Time::HiRes qw( sleep );

use constant LINES_PER_SECOND => 100;

our $lps ||= LINES_PER_SECOND;
our $h;

if ( $h ) {
    die <<END_USAGE
usage: $0 [-lps=100]
  lps: is lines per second
END_USAGE
}

my $sleep_seconds = 1 / $lps;

$|++;

while ( <> ) {
    print;
    sleep $sleep_seconds;
}

exit;