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Chmod, Umask, Stat, Fileperms, and File Permissions

Unix file permissions are one of the more difficult subjects to grasp.. Well, ok maybe "grasp" isn't the word.. Master is the right word.. Unix file permissions is a hard topic to fully master, mainly I think because there aren't many instances when a computer user encounters them seriously, and bitwise is oldschool. This contains a listing of all possible permission masks and bits from a linux, php, and web hosting view.... cuz you guys AskApache Regs Rock!

Security

PHP Session File Hacks

What they say about kung-fu is true..

It can be attained by anyone through hard work over time. You can become as good as the amount of work you put in. Here's a short look at a basic technique that I use. Simply reverse engineering the source code and taking notes along the way...

static void php_session_send_cookie(TSRMLS_D)
  if (SG(headers_sent)) {
          if (output_start_filename) {
                  php_error_docref(NULL TSRMLS_CC, E_WARNING, "Cannot send session cookie - headers already sent by (output started at %s:%d)",
                          output_start_filename, output_start_lineno);
          } else {
                  php_error_docref(NULL TSRMLS_CC, E_WARNING, "Cannot send session cookie - headers already sent");
          }
          return;
  }

  /* URL encode session_name and id because they might be user supplied */
  e_session_name = php_url_encode(PS(session_name), strlen(PS(session_name)), NULL);

PHP

Caching Tutorial for Webmasters

If you examine the preferences dialog of any modern Web browser (like Internet Explorer, Safari or Mozilla), you'll probably notice a 'cache' setting. This lets you set aside a section of your computer's hard disk to store representations that you've seen, just for you. The browser cache works according to fairly simple rules. It will check to make sure that the representations are fresh, usually once a session (that is, the once in the current invocation of the browser).

Optimization

SEO with Robots.txt

Very nice tutorial dealing with the robots.txt file. Shows examples for google and other search engines. Wordpress robots.txt and phpBB robots.txt sample files.

SEO