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UPDATE: Why some people better shouldn’t play admin

November 21st, 2008 by TheBonsai

Ha! A rant!

Yesterday someone gave me a link… The 7 deadly Linux commands

It sounded interesting, so I started to read. The whole thing was about 7 ways to (permanently or temproraily) kill a Linux system. I picked 4 below.

I didn’t trust my eyes, not only that the initial article has some really serious bugs, especially the comments are really amazing. That looks like an own “dailyWTF” for administration!

The initial article

  • #1: rm -rf /: This definitely can work :) but the author simply forgets to mention that you may need to gain some interesting permissions first, you know: God, root – where’s the difference?
  • #2: The hexified literals: Every kid can decipher that, provided it can read wikipedia articles or somesuch – heh. And when you search good enough, you find out what it is (a faked sudo attacking method – to catch script kiddies and wannabe hackers, nothing serious)
  • #4: The good old Bournish fork bomb: How nice – but with proper ulimits set, nothing interesting will happen (though some comment explains this as “has been fixed in modern systems” – as if it was a bug or so…)
  • #7: mv /home/user/* /dev/null: That’s a nice one, especially when you believe the article, which says that your files will be lost, away, gone – because /dev/null is the bit bucket! Amazing! Even if I’m root, the only thing I’ll loose is a device node 😉 Beside the fact of target file not being a directory and whatever else you can hit here.

Provided that the author really meant it serious, and the article was meant to warn newbies, that’s not that bad afterall. Newbies don’t need details in their first days – and this article is meant to make their system survive until they know the details. The intention isn’t bad, so.

The best: The comments!

I would have expected that 99% of the comments to this article are from people who shake head and maybe explain the wrong stuff a bit – but no, just a few comments are okay, looks like handselected. Many comment were just more technical crap!

I picked one “comment thread” to show you, many others were not really better:

rm -fr * is the same as rm -fr /

  • The very first comment says that! rm -fr * is the very same. Let’s follow the thread.
  • Some guys (“Chuck” and others) corrected this comment, with a brief description what the difference is.
  • “jdhore1” explains why rm -rf * must be the same: “* means everything that includes the . and the .. you see when you do ls -a” and “On unix machines this will jump a directory […]”. That’s not enough, here a small hammer: “[…] this doesn’t apply on most kernels […]just make your own thoughts about this stupidity! This guy will be the first one who crashes his system because of dangerous half-knowledge, not a newbie.
  • Finally a guy who knows what he’s talking: “I know of no shell in all history that has included . and .. in * globs by default.”maybe the world isn’t as bad as I though until this comment!

Have fun reading the entire page. It’s worth, you’ll feel better afterwards.

Ha – I found a really nice one, one trying to be smart and correcting the article’s point #7 (mv to /dev/null) a bit:

“You can change the last one (mv /home/yourhomedirectory/* /dev/null) to this: mv ~/* /dev/null”

….which is of course correct, but what bugged me on that comment is the name and the blog-link of the commenter: The Unix Geek

Hell, why doesn’t a guy named “UNIX geek” provide corrections? Instead he behaves as if everything told above was correct and right… Get another name, dude.

And people, think about one thing:

Your job as system administrator is safe, regarding all the alternatives that published their “skills” on that page!

UPDATE-01: (german) Und jeder schreibts wirklich schlau ab ohne es zu verstehen. Nach meinen Recherchen sind nun schon 2 grobe Fehler in dem Ding. Ich glaube der Typ hat es auch nur irgendwoher zusammenkopiert ohne es selber zu verstehen.

This entry was posted on Friday, November 21st, 2008 at 06:46 and is filed under english, Hobby, Linux. You can follow any responses to this entry through the RSS 2.0 feed. You can leave a response, or trackback from your own site.

3 responses about “UPDATE: Why some people better shouldn’t play admin”

  1. Usn said:


  2. wehdehpeh said:

    rofl… soviel mist, tut doch schon weh.. Ich wette er hat nen Crashkurs besucht – in 2 Wochen zum Linux Crack.

  3. Jeans Weblog » Linux hat so seine Tücken… said:

    […] Bonsai’s Blog […]

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