Re: How to convert a md5sum back to a timestamp?

[Stephane Chazelas]

2019-08-01 02:08:59 -0600, Assaf Gordon:
[...]
> Three notes:
> 1.
> I would recommend using "-%7.0f minutes" format in "seq"
> instead of "%g", as the latter will result in a scientific notation
> for large values:
> 
>    $ seq -f '-%7g minutes' 2563200 | tail -n1
>    -2.5632e+06 minutes
> 
>    $ seq -f '-%7.0f minutes' 2563200 | tail -n1
>    -2563200 minutes

Good point, though 
$ seq -f '-%7.0f minutes' 1
-      1 minutes

You'd want:

seq -f '-%.0f minutes' 2563200

Or

seq -f '%.0f minutes' -- -1 -1 -2563200


[...]
> For reference, on my old desktop it takes:
> 
>     $ time seq -f "2019-08-01 01:53:22Z +%7.0f minutes" 2563200 \
>           | date -u -f - +%Y%m%d_%I%M%p \
>           | datamash --full md5 1 | wc -l -c
>     2563200 125596800
> 
>     real    0m14.185s
>     user    0m17.739s
>     sys     0m0.527s
> 
> And results in ~125MB of data - reasonable for an ad-hoc reverse
> lookup table for MD5 values.
[...]

Thanks. I definitely need to have a better look at datamash.

-- 
Stephane