[TriLUG] cpio checksum errors

[Ed Blackman via TriLUG]

On Fri, Apr 28, 2017 at 10:34:42AM -0400, Paul Boyle via TriLUG wrote:
> Out of about 70,000 files, I got 107 checksum errors. Typically it
> looked like this (sorry for the line wrap):
> 
> cpio: boyle/Pictures/2008-08-02/2088-08-24/MVI_0075.AVI: checksum error
> (0x1ce87d5a6, should be 0xce87d5a6)
> cpio: boyle/Pictures/2008-08-02/2088-08-24/MVI_0034.AVI: checksum error
> (0x1337929d6, should be 0x337929d6)
> cpio: boyle/Pictures/2008-08-02/2088-08-24/MVI_0032.AVI: checksum error
> (0x1c23725ea, should be 0xc23725ea)
> 
> I  haven't checked all of the files.  There were some PDFs which gave
> errors and those opened in okular OK and I didn't notice any gross
> errors.

I have no idea what the cpio error message means, but you can easily 
verify that the files are byte-for-byte equal.

Since you have a precise count of the errors, I presume that you have 
text file with those errors in it.  I would run:

  cut -d: -f2 errors.txt | while read file; do sha1sum "$file"; done > verify.txt

Note that if there are files with embedded newlines in the file name 
you'll get some error messages, and will need to check those files 
manually.  If you don't have sha1sum on both systems, md5sum will do.  
Even cksum (usually installed by defaul) is fine, though it will make 
verification harder.

Move verify.txt over to the other system, and run sha1sum -c verify.txt.  
You'll get a report of which files are the same and which differ.

-- 
Ed Blackman
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