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

my $random = '/dev/prandom';
my $zero = '/dev/zero';
my %files;
$files{$_} = int(-s $_) foreach (@ARGV);
open(RAND, "<", $random);
open(ZERO, "<", $zero);

foreach my $file (keys %files) {
  print "$file: $files{$file}\n";
  foreach my $num (1..5) {
    open(FILE, ">", $file);

    foreach (0..($files{$file} / 1024 + 1)) {
      read(RAND, my $rand, 1024);
      print FILE $rand;
    }
    close(FILE);
    open(FILE, ">", $file);

    foreach (0..($files{$file} / 1024 + 1)) {
      read(ZERO, my $z, 1024);
      print FILE $z;
    }
    close(FILE);
  }
  unlink($file);
}

close(RAND);
close(ZERO);

[download]

In reply to Does this script securely delete data? by Anonymous Monk

Title:
Use:  <p> text here (a paragraph) </p>
and:  <code> code here </code>
to format your post, it's "PerlMonks-approved HTML":


  • Posts are HTML formatted. Put <p> </p> tags around your paragraphs. Put <code> </code> tags around your code and data!
  • Titles consisting of a single word are discouraged, and in most cases are disallowed outright.
  • Read Where should I post X? if you're not absolutely sure you're posting in the right place.
  • Please read these before you post! —
  • Posts may use any of the Perl Monks Approved HTML tags:
    a, abbr, b, big, blockquote, br, caption, center, col, colgroup, dd, del, details, div, dl, dt, em, font, h1, h2, h3, h4, h5, h6, hr, i, ins, li, ol, p, pre, readmore, small, span, spoiler, strike, strong, sub, summary, sup, table, tbody, td, tfoot, th, thead, tr, tt, u, ul, wbr
  • You may need to use entities for some characters, as follows. (Exception: Within code tags, you can put the characters literally.)
            For:     Use:
    & &amp;
    < &lt;
    > &gt;
    [ &#91;
    ] &#93;
  • Link using PerlMonks shortcuts! What shortcuts can I use for linking?
  • See Writeup Formatting Tips and other pages linked from there for more info.