I was running bittorent on my external HDD (which had ext3).
Suddenlly the bittorrent client gave a write error, and all the files in the external HDD vanished.
How should I do a disk check ?

Also, what is the best filesystem for an external HDD ?

fdisk and fsck
the man pages for each of these are quite readable.

the best format for an externel hdd is FAT32 because all operating systems can read it

The filesystem is ext3.

I did this:
The filesystem is ext3 ad not ext2

Use the device for the partition, and not the disk.

Try /dev/sdb1 instead.

If you still get that error, then look at the output of "tune2fs -l /dev/sdb1". It may provide information on the locations of the alternate superblocks.

Yup, that did the trick.
However there were thousands of errors. I got tired of presssing y after a while (it would not accept the a option).

I reformatted it, but now it seems the HDD has died

now it seems the HDD has died
... this is usually the case.

... "best" is not a good descriptor as it is just sooo subjective. B'sides, you have based your assessment on only one metric.

eg. fat32 is a poor choice as it is non-journaling and doesn't preserve permissions - it also responds poorly to unclean disconnections, which are more likely in an external drive - these things may outweigh the desire for portability, especially if the client is happy to install alternative fs support to non-linux machines.

If the drive needs to store very large files, or needs to be able to handle a great number of small files rapidly, the equation changes again.

See how the inclusion of other metrics changes your assessment. There was simply not enough information to make a recommendation.

Further, OP's issue was about a bad drive... using a different fs probably wouldn't have helped. It fact, ext3 at least offered some hope of recovering the lost data. (ext2 would, maybe, have been easier in this regard.)

You're normally more thoughtful than this... had a rough night?

He asked what the best filesystem was for externel harddrives, I'm used to flashdrives that have to be read on windows and linux machines

Sorry.
Say I'm only using the the external HDDs with linux.
And I'm using the external HDD extensively with bittorent.

... amday! I could have sworn I checked: 10:08pm (nz time) isn't too late either so I don't get to plead the 2am-effect

Don't flashdrives come pre-formatted with fat32 on a logical partition?

Windows won't make fat32 bigger than about 32GiG and I understand Vista won't creat fat32 at all(?) <checks> in-ter-rest-ting...http://www.lavafactory.com/articles/...ing-limitation
... I am guessing this command uses 32k blocks.
Note the Windows shift back to the commandline!

Anyway... the upshot is that the "best is subjective" rant should have been directed at OP... who, I see, has got the message. Cool.

is there a reason why you have to constantly criticize my posts?

is there a reason why you have to constantly criticize my posts?
... that is an excellent post: direct and to the point. Well done

If you add the -y flag you won't have to hit yes each time. If you tried to fsck the device "/dev/sda" it could cause serious filesystem damage. As could fscking while mounted.

Please properly capitalize sentences, it's just hard to understand if you don't.

I was talking to Simon Bridge