On: Count to ten when a plane goes down

[kstenerud]

The worst unix disaster I ever saw happened to one of my co-workers. He was working on a client machine, logged in as root because he needed to compile and install some complicated software. As he was working, he did an ls -l /bin and copy-pasted it to a text editor so he could make sure everything was installed correctly. Unfortunately, after returning to his console, he accidentally hit paste. Most of /bin was actually symlinked somewhere else. As you know, ls shows symlinks like this:

lrwxrwxrwx 1 root root 20 Apr 27 17:02 cc -> /etc/alternatives/cc

Guess what happens when you paste a whole list of those into a console as root?

[lcedp → kstenerud]

That's fascinating.

To prevent this from happening with me, I've added the following line to my `.Xdefaults`

    URxvt.perl-ext: confirm-paste

(I'm using `rxvt-unicode`)

http://i.imgur.com/joHRXaH.png

[talmand → kstenerud]

The worst unix disaster ever? Could you elaborate for non-unix people such as myself?

[smwht → talmand]

The important character here is the '>'. This redirects output to a file and overwrites the file. The lrwxrwxrwx will only print an error, but the redirect to the target executable will erase the target.

For example:

  $ echo "asdf" > foo
  $ cat foo
  asdf
  $ lrwxwrwxrwx 1 root root -> foo
  lrwxrwxrwx: command not found
  $ cat foo
  $

So basically, this zero'd out every executable on the system.

[talmand → smwht]

Yep, that's bad.

Out of curiosity, what was the solution to fix all that?

[mianosm → talmand]

Possibly a cp or an scp from a remote system with a working set of binaries.

[kstenerud → talmand]

scp was in /usr/bin, so we could at least copy enough basics from another system and recover the rest from a backup. Needless to say we lost the client contract.

[Tyr42 → kstenerud]

Oh no, that redirect!