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Comment by colemannugent | Hacker News Reader

One thing I'll often use dd for is recovering data from a failing drive. Can head ignore read errors? dd can.

As far as I'm concerned, dd is lower-level than most of the other utilities and provides more control over what's happening.

The author does have a point that the syntax is strange though.

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dd is awful and error-prone for this sort of use.

Use noerror, but forget sync? Corrupt output file if there is an error. Use a bigger bs so it's not slow as treacle? A single faulty sector blows away a whole bs of data, and your output image may get unwanted padding appended to the end. Recoverable error? dd's not going to retry.

Use ddrescue or FreeBSD's recoverdisk(1). They're faster, they're safer, they're more effective, and they're easier to use.

ddrescue is excellent.

ddrescue is so good that that particular example feels a little strawman-ish

GNU ddrescue[1] and not dd_rescue[2]. I'm adding this precision because depending on the linux distros dd_rescue package name may be ddrescue and GNU ddrescue package name may be gddrescue.

[1]: http://www.gnu.org/software/ddrescue/ddrescue.html [2]: http://www.garloff.de/kurt/linux/ddrescue/

I use gnu ddrescue for this for its ability to log and retry failed areas. Can make recovery or verifying data easier

>One thing I'll often use dd for is recovering data from a failing drive.

Funnily enough, I ended up using it to accidentally name the wrong drive in the argument, and lost years of photos, music, video etc. though I suppose I can't blame dd for that :)

Don't drink and dd. Spoken from experience.

I think there's a rule that you're not really qualified to discuss command line tools in public until you've used dd to inadvertently eradicate an entire partition.

Personally, I'd add the use of a trailing full-stop in an rsync command in the wrong directory (e.g. in /home/user) as an alternative qualification to your rule.

I now use full paths for destination as well as source.

I thought dd could be used for this purpose and ended up with a dead drive and an unusable partial image. Now I know better and use GNU ddrescue.

Personally I prefer safecopy.

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