john-users - --show=LEFT output

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Date: Sun, 6 May 2012 19:44:15 +0200
From: Frank Dittrich <frank_dittrich@...mail.com>
To: john-users@...ts.openwall.com
Subject: --show=LEFT output

Hi all,

we had a similar issue mentioned by magnum in the past, see
Message-ID: <4D824B35.5020908@...dband.net>
http://openwall.com/lists/john-users/2011/03/17/1
http://thread.gmane.org/gmane.comp.security.openwall.john.user/3347/focus=3524

$ cat passwd
user1:XXxzOu6maQKqQ:1001:1001:user 1:/home/user1:/bin/bash
user2:XXxzOu6maQKqQ:1002:1002:user 2:/home/user2:/bin/bash

$ ./john --show=LEFT passwd
user1:XXxzOu6maQKqQ

The --shown=LEFT output gets rid of information which might still be
helpful for cracking the remaining hashes.

Instead of just suppressing lines containing hashes which have been
cracked, --show=LEFT output removes all columns except user name and
hash, and it also prints each uncracked hash just once, even if it
appears multiple times in the input file.

This is unfortunate, because the information which is missing in john's
--show=LEFT output could still be useful for further cracking sessions,
especially for single mode.

Can we just change the behavior of --show=LEFT, possibly breaking some
scripts which rely on the current poutput? Or do we need to support the
current behavior in the future, so that a new --show=??? option is required?

Frank