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Comment by chrisfosterelli | Hacker News Reader

I think dd is primarily so popular because it is used in mostly dangerous operations. Sure, using cat makes logicial sense, but if we are talking about writing directly to disk devices here I'll trust the command I read from the manual and not explore commands I think would work.

dd's "highly nonstandard syntax" comes from the JCL programming language, but it's really just another tool to read and write files. At the end of the day it's not more complex or incompatible than other unix tools. For example, you can also use tools like `pv` with dd no problem to get progress statements.

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There is some truth to the fact that (if you basically already know dd like I do) then reserving it for dangerous operations is a good way to "signal" to yourself "slow down here and pay attention"

I always thought dd stood for disk destroyer, only ever used it for making low level copies of whole disks or shredding them with if=/dev/random. This thread has been informative and terrifying as I learn cat and cp are every bit as dangerous as dd! I never would expect something like cp xxx /dev/sda to actually work. Thinking about it, why should cp even support something like that? I'll copy files but I'll also DESTROY YOUR SHIT if you say so?

I'll also DESTROY YOUR SHIT if you say so?

It better :-)

But it all comes from the unix idea of everything is a file.

> I never would expect something like cp xxx /dev/sda to actually work. Thinking about it, why should cp even support something like that? I'll copy files but I'll also DESTROY YOUR SHIT if you say so?

That's the beauty of Unix.

Everything is a file. Thus every program that can work with files, can in fact work with everything.

It's actually very liberating.

It isn't the same though, because not all files are non-seekable streams of bytes. In fact, most are seekable and possibly sparse.

What happens when you did a sparse file? And cp?

https://wiki.archlinux.org/index.php/sparse_file

C.f. fallocate(1,2)

> I'll also DESTROY YOUR SHIT if you say so

That's the Unix way: The customer, eh, user is always right.

I once wanted to clean up backup files created by emacs (they end in the tilde character) by typing "rm <asterisk>~" - except what I did type was "rm <asterisk> ~".

(On the upside, I learned a valuable lesson that day.)

1. Everything is a file; why would cp care that one file happens to be your hard drive?

2. "UNIX was not designed to stop you from doing stupid things, because that would also stop you from doing clever things."

- Doug Gwyn

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