Monthly Archives: February 2009

Secure Delete Files in Terminal on OS X

Securely delete files on Mac OS X in the Terminal by using srm:

srm <filename>

This will delete the file, then rewrite random data over the spot on the hard disk where the file was previous stored several times to prevent any file recovery attempts.

A regular delete using rm in the Terminal will only remove any pointers to the file itself, but this information can be recovered using file recovery and undelete tools.  This is similar to erasing an entry in the telephone book for someone’s house and phone number; the house is still standing and telephone number is still valid.  Using srm would send a bulldozer to the house to tear it down and break it into bits so small, it would be difficult to tell that a house ever stood there.

Securely deleting files is useful when you need to destroy a password file.  For example, I keep a file that is pgp encrypted with all my passwords within it.  When I need to add new passwords, I decrypt the file, add the new username/passwords, then re-encrypt the file.  Afterwards, I need to securely destroy the text file that I updated.  For that, I use srm.

Read more about srm at Wikipedia.

Firefox Stops Loading Pages – Fix

Firefox stops loading pages after several hours or days of continuous use.The problem often starts with only some page loading errors: stylesheets not being applied (ugly white pages with no images), buttons not working, forms not submitting, etc., then quickly gets worse until Firefox is completely unusable and often cannot be restarted.

Sound familiar?

The problem has to do with Adobe Flash Player.

firefox_302

Symptoms

Common symptoms of the Firefox loading problem:

  • web page buttons in Firefox stop working (clicking doesn’t do anything)
  • links stop working (clicking links produces no action)
  • parts of web pages stop loading in Firefox (or Camino)
  • stylesheets stop being rendered or applied, which make pages show up with:
    • a plain white background web page,
    • 1994-style bright blue links,
    • plain times new roman font text,
    • simple bulleted lists,
    • borders on table cells.
  • new tabs or windows show up completely blank
  • Firefox won’t quit or shutdown

When Firefox stops loading pages properly, the problem begins with subtlety, then the situation degrades quickly until Firefox is completely unusable.  Previously, the only solution was to restart Firefox, killing the Firefox process (using Activity Monitor – Quit Process) if Firefox wouldn’t shutdown properly.

This solution was only a temporary fix with the root Firefox page load problem still there.  Clearing the cache in Firefox, then restarting, also seemed to help reset the loading problem on Firefox, up until it starts again after several hours or days of web surfing.

Fixing “Firefox Stops Loading Pages” Problem

A permanent fix to this Firefox loading problem: upgrade Adobe Flash Player to version 10 from version 9.  Strangely, Mozilla/Firefox nor Mac OS X Leopard never recommended this update, even when Adobe published version 10 of Flash Player, wheres Firefox 3 comes by default with Flash Player 9, and actually, still does.  Perhaps Mozilla considers Flash Player a system component, rather than a browser component and doesn’t notify Firefox users of updates to such pieces of software.  This seems a bit odd to me, considering the only time I use Flash Player… is with web browsers, regardless of whether its Firefox, Safari, or Camino.

Step 1: Check your version of Adobe Shockwave/Flash in Firefox

Open a new Firefox tab or window.

In the address bar type in about:plugins and hit enter.

Firefox About Plugins

This will load a special Firefox configuration page showing you all the plugins installed for use with your version of Firefox.

Scroll down to the bottom until you see a heading for Shockwave Flash.

Firefox Flash Version

The key piece of information in this section is just above the blue bar where it reads: Shockwave Flash 9.0 r115

This tells me that I’m running Adobe Flash player version 9 and what I need to do is upgrade to Flash version 10.

Update: Another way to check which version of Flash Player you have installed is to visit Adobe Flash – About page, which will tell you your currently installed Shockwave Flash version (bottom right hand corner in the Version Information box.)

adobe_flash_installed_version

Step 2: Download & Install Adobe Flash 10

In Firefox (or any browser) go to http://get.adobe.com/flashplayer/. You’ll see this page:

Adobe Flash 10 Mac Download

Click on the big bright Agree and Install Now button.  Let Adobe install Flash 10 on your computer.

After the install is complete, we can check that Flash 10 has been installed.  Restart Firefox and again visit the about:plugins configuration web page.  You should now see the following:

firefox_flash_10_upgraded

Congratulations. You’ve upgraded to Flash 10. Firefox should now be able to load web pages continually, without restarting/cache clearing, no matter how long you keep Firefox open and running.

I’ve been running with Firefox 3.0.2 on Mac OS X 10.5.2 Leopard with Adobe Flash 10 for nearly a month now and Firefox hasn’t stopped loading pages once after having upgraded to the new version of Flash Player.  I’m confident this is a permanent fix for those who’ve been running Firefox with Flash 9 and have been troubled by the eventual page load problem.

(I want to thank unsound of the Mozillazine Forums for pointing me in the right direction with this problem.)