cksum entire dir??

Matthew Seaman matthew at
Wed Sep 12 06:32:08 UTC 2012

On 12/09/2012 00:14, Polytropon wrote:
> 	% cksum <directory>
> and could obtain a checksum - so it _seems_ to work.
> After alteration of one file within the hierarchy a
> different result was printed.

That will give you a checksum on the directory inode -- file names and
associated metadata only, not file content.  In theory you could edit a
file without modifying any of the timestamps, and that wouldn't result
in any change to the directory checksum.  Also, modifying things a few
layers down the filesystem hierarchy won't have any effect either.

Generally I find the best test for differences between old and new
copies of a filesystem is 'rsync -avx -n ...'

Also, sum and cksum have way too small a key size for this to be
reliable, since you can't tell a true result from a hash collision.  Use
md5 or sha1 or sha256 for best results.



Dr Matthew J Seaman MA, D.Phil.

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