sha256sum

[Bill Davidsen]

stan wrote:
> On Thu, 18 Jun 2009 20:24:56 -0400
> terry <xtlynne at charter.net> wrote:
>> Todd
>> I interpret the above as ... sha256sum Fedora-xxx-xxx-CHecksum and
>> the program looks for the iso and calculates the number and checks
>> them with the checksum file for a match or no match? No? If so, this
>> doesn't work. It is the same answer as Steve Searle's and Doc
>> Savage's. I think more detail is needed.
>>
> As it happens, I just downloaded the f11 dvd today and ran a check on
> it.  I used the program shasum with the checksum file for F11 I
> downloaded.
> 
> In a directory with both the Fedora iso file and the iso's checksum-file 
> present, run the command:
> 
> shasum -c checksum-file
> 
> This will read the list of checksums in the file, and look for the
> files that generated those checksums in the present directory.  It will
> then run the same check on them that the checksum was generated with in
> the file. It will compare the two checksums and tell you if they are
> the same.
> 
> Clear as mud? :-)
> 
I have had two people (so far) tell me their bittorrent was missing files 
because the CHECKSUM file has all the possible files in it. I therefore offered 
them this tiny script which they can run in any directory:
   for fn in *.iso; do grep "$fn" *CHECKSUM; done | sha256sum -c -

It is so easier than explaining that only the lines for images they have are 
meaningful. Users, one told me they didn't check downloads because they didn't 
know what to do if there was an error.

-- 
Bill Davidsen <davidsen at tmr.com>
   "We have more to fear from the bungling of the incompetent than from
the machinations of the wicked."  - from Slashdot