Paranoia seemed to light this gals fuse.

Bet she won't do that again.

http://www.foxnews.com/story/0,2933,325285,00.html

 

Damn! Yes it is never safe to ASS u ME anything
Glad the guy was able to recover files... not many people know how to truly delete things from a computer. It's alot more work than just pressing the delete key

 

That's not really any harder to type out than:

Taking a sledgehammer to the hard drives is probably more fun, though.

 

That firm was so smart they even knew what the word backup meant, oh wait, no they didn't...

 

By the way ... why was she looking at job listings anyway?

 

Maybe I should start one of those "expensive data recovery" services.

 

That's why "hidden" directory names (".xxx") was invented, to avoid this.

 

Actually, that command would blow away all such hidden names anywhere below the "/" level, which generally would mean all of them.

But that just tells the OS that the disk space is free to be reassigned. It doesn't actually write over it.

The dd command (all of these are *nix commands) writes a stream of bits from an input file to an output file. It is usually used to make bit-by-bit clones of entire disks. But that command I posted would generate a random stream of 1s and 0s and then write them over every location on an entire disk. (/dev/hda is the first hard drive installed in the machine. /devhdb is the second. Etc.)

What I don't know for sure is whether the whole thing is done in RAM and BIOS. If so, then it wouldn't matter that dd is writing over itself. Otherwise, when you overwrote enough of the OS then the computer would stop working and some of the data would remain. But anyway, the point is that to really erase a disk you want to write random bits to it, not just to delete the pointers to the various file fragments.

(By the way, "rm" stands for "remove" but "dd" doesn't really stand for anything. However, Unix sysadmins will often tell you it stands for "destroy disk", because the slightest error in using it can have some really bad consequences.)

My guess is that these were probably Windows boxes and she probably just did a "Format C:" type of thing. In any event, she must not have written random data over the existing data -- if she had then the "expensive recovery service" would have essentially had nothing to work with.

 

Not true. If you have typed "rm -rf /" that would be the case. However, by typing "rm -rf /*" the shell would expand the "/*" to a list of directory (or file) names which will not include any hidden files (or directories) at that level. So the net result is that all "visible" files/directories are removed but the hidden ones will remain. Go try it on your system and see what happens.

edit: I heard that "dd" stood for "data dump", don't know if it's true. You can use it to convert from EBCDIC to ASCII and swap bytes, very useful when moving between DEC and IBM machines in the old days.

 

The wildcard will only expand to the / level directories. Then the -r will take over and recursively delete everything in each of them. At least, that's how it seems like it would work. (And in fact, I just did a test using a set of dummy directories. It did correctly delete all the hidden subdirectories below the first level, and also the hidden files in the subdirectories.)

But yeah, leaving off the wildcard is probably the "better" choice.