Directory hashing

[Aki Tuomi]

> On 11/05/2020 11:21 lists at mlserv.org wrote:
> 
>  
> > Am 11.05.2020 um 10:16 schrieb Aki Tuomi <aki.tuomi at open-xchange.com>:
> > 
> > 
> >> On 11/05/2020 11:10 Simone Lazzaris <s.lazzaris at interactive.eu> wrote:
> >> 
> >> 
> >> In data lunedì 11 maggio 2020 10:00:38 CEST, lists at mlserv.org ha scritto:
> >>> Hi,
> >>> 
> >>> I struggle with directory hashing. I want something like this:
> >>> 
> >>> /srv/mail/c/cf37a8dff5e360927ba10ab2
> >>> 
> >>> The final folder is simpel, as it is:
> >>> 
> >>> %{sha256;truncate=96:user}
> >>> 
> >>> But how do I get a first level from sha256? Unfortunately, the truncate
> >>> option aligns only full 8bit and does not divide into low and high nibbles.
> >>> How can I express this for sha256?
> >>> 
> >>> in MD5 this would be %1Mu
> >>> 
> >>> Many thanks in advance
> >>> 
> >>> Christian
> >> 
> >> Maybe as a workaround you can create a directory named /srv/mail/c and make 16 
> >> symbolic links to it: /srv/mail/c0, /srv/mail/c1, /srv/mail/c2,  up to /srv/
> >> mail/cf.
> >> 
> >> In that way you can use truncate=8.
> >> 
> >> 
> >> 
> >> -- 
> >> Simone Lazzaris
> >> QCom SpA
> > 
> > Out of curiosity, but why do you use SHA256? You get probably no extra benefit from it. I mean, you are free to do so, but ... why?
> 
> The reason for me was that I could bash script a transition from username to directory:
> 
> echo -n "username" | sha256sum | cut -c 1-24
> 
> That way I could convert all folders easily. I did not know how to do this with the M-versions.
> 
> > 
> > Anyways, it would work pretty much the same way, %1{sha256:..} and %4{sha256:...}.
> 
> Thanks. I will try that out.
> 
> Christian

%M = 'echo -n username | md5sum'

The %1 means take first hex nibble.

Aki