why does -i paremeter not working while pipe?

[DKblue]

It's very easy to think about this:
you have 2 different processes
the 2 processes only communicate over the pipe
the second hashcat instance only knows that it gets some input from stdin (from an *external* command/process)


There is no way that the second hashcat instance could know what the first one is generating and therefore the second (main) hashcat process can't show how many candidates are left and on which mask it is currently working etc.

This is always true and this is the basic principle how pipes work in general

Short answer: everything is working correctly. 2 distinct processes only communicate by use of a pipe but where the only data that is sent is the password candidates and therefore the second process can't know at which mask position the first process currently is

So according to your "Short answer: everything is working correctly" ,my code -a6 wordlist.txt ?l?l?l?l?l -i can cover all ranges from 
a
aa
......
zzzzz
Although I can't see the mask running progress.
Is that so? Sorry for my newbie question and thanks for your quick reply.
Thanks again