/dev/chat

9:00 AM

@ilkkachu come on, please don't drag out irrelevant conversations in the comments. I told the OP that they should never run commands blindly without knowing what they are. Of course that applies to cat as well, I never said otherwise!

(re unix.stackexchange.com/questions/669981/…)

But, also obviously, it is much easier to misunderstand "dd if=/dev/null of=/dev/sda" than "cat /dev/null > /dev/sda" since the 'if' an 'of' are very similar and only differ in one letter.

I am not saying that dd is inherently more dangerous than cat. Hell, all I was saying is that you shouldn't blindly run commands!

Andras Deak

surely nobody would run anything they don't understand... :P

And I think sudo cat doesn't work like that due to the redirect, so you have to work a bit more for that. Of course you can still overwrite your ~.

terdon

9:16 AM

yep

or run as root

ilkkachu

@terdon No, that's exactly what you were saying: "Especially if that command is dd, a very powerful and unsophisticated tool" and "even more important with something like dd that can be missused so easily." And exactly what I was objecting to.

terdon

@ilkkachu Yes. That is what I am saying if you completely ignore the first sentence which is in italic bold font for emphasis. Sure, if you take something out of context and fixate on it, and then also ignore the explanation I gave above, you can read it that way.

But even if you do read it that way, if you honestly cannot see that running 'sudo dd if=/dev/null of=/dev/sda' is much easier to happen by mistake than running 'cat /dev/null | sudo tee /dev/sda', then I don't really know what to say and we can agree to disagree. As far as I'm concerned, the syntax of dd makes it orders of magnitude easier to missuse.

ilkkachu

@terdon "ignore the explanation"? I didn't see anything in the comments backing up the claim that dd would be more dangerous than any other command. Those quotes were from the comments, from the part I objected to. Yes, you said it here that you think if and of are similar, and ok, perhaps they can be confusing (if one doesn't realize the connection to "in" and "out"). But like I said, < and > are also just one character apart, and on the same or neighboring keys on many keymaps too.

@terdon there was no sudo there.

terdon

@ilkkachu That's probably because I never claimed that dd is more dangerous.

I said "don't run commands you don't know". And then I said that is especially applicable to dd. Not because it is more dangerous (that's how you chose to read it) but because the syntax is obscure ("unsophisticated tool") and very easy to get wrong.

ilkkachu

@terdon well, you twice pulled it as an example of a particularly dangerous command, so yeah, one might get the impression you think it is somewhat more dangerous than a random other command, no?

terdon

9:28 AM

@ilkkachu Yeah, OK. I'll ask another mod to clean up the comments. Next time, please take this sort of thing to chat instead of continuing in the comments.

ilkkachu

@terdon yeah ok. What I saw there, was that you answered my comment by basically just repeating what you said the first time. Instead of giving any new information, rephrasing your point in some other way, or moving to chat immediately. But I guess that's fine, since you can ask someone to just delete the comments?

@terdon also, I do honestly think the biggest issue with commands like that is mistyping the target partition. It doesn't matter if the command there is dd or cat or tee or fdisk or wipefs, if one types the wrong device name, then bam. They're usually one character away.

terdon

@ilkkachu Yes, I repeated that you shouldn't run commands if you don't know what they do. And of course that is even more true of commands like dd than commands like echo.

@ilkkachu exactly

which is why you shouldn't run them blndly and then come here to ask what they do.

ilkkachu

@terdon well, at least we agree on that part :D

Stephen Kitt

The biggest mistake is not running commands one doesn’t understand, it’s not having up-to-date backups which can easily be restored ;-).

Although running commands one doesn’t understand can have bad consequences other than losing data, so I guess that is really the bigger mistake here.

ilkkachu

@StephenKitt ooh! well said

Stephen Kitt

9:42 AM

(Recent instances here which resulted in users installing cryptominers spring to mind.)

ilkkachu

I was wondering if you meant something like that or actually breaking stuff. What was the thing about a filesystem interface to some EFI parameters was left read-write, and then you could trash the EFI settings with an rm -rf ...

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