PIPE_BUF test

pipe_buf_test.pl

#!/usr/bin/env perl
use v5.10.1;
use strict;
use warnings;
use Fcntl ':DEFAULT';

# Usage:
#    >/tmp/append; perl pipe_buf_test.pl /tmp/append A $((2**12)) 4
# Will write 4 lines of 4095 "A"s and \n to /tmp/append
my ($file, $byte, $length, $times) = @ARGV;

my $str = ($byte x ($length - 1)) . "\n"; # -1 for \n

sysopen my $fh, $file, O_WRONLY|O_APPEND|O_CREAT, 0666 or die $!;
for my $n (1..$times) {
    syswrite $fh, $str or die "Failed to write() the ${n}th time: $!";
}
close $fh or die $!;