[tz] question about SHA512 when using tzdata

Paul Eggert eggert at cs.ucla.edu
Sun Oct 18 02:19:57 UTC 2015

Brian Inglis wrote:
> see info sha2

Ah, in that case I guess we're talking about the same software. On Ubuntu 
sha512sum (which is the 512-bit version of SHA-2) does not output '*' by 
default. One must use the -b option to get the '*'. For example:

$ sha224sum Theory
685a1c44d638eabaf90721c599ebc87dabfa1eaecafcf320b0b37cf9 Theory
$ sha224sum -b Theory
685a1c44d638eabaf90721c599ebc87dabfa1eaecafcf320b0b37cf9 *Theory

The checksums are the same either way. As I understand it, the Coreutils SHA-2 
programs behave differently on platforms like MS-Windows that distinguish text 
from binary I/O, and they make -b the default there.

Ian Abbott is suggesting the '*' form so that the checksums can be checked more 
easily on MS-Windows. We can do that on Ubuntu by using -b. The '*' will also 
likely confuse users on other platforms (it's certainly confused *me* in this 
thread...) but perhaps it's worth the hassle.

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