How to know the number of characters in a password ?

[plaverty9]

Along the lines of what Royce said, start small. If you have a fast enough hash type, you can brute for an entire space relatively quickly. For example for NTLM, I've been able to hit everything with the 95 characters for up to 7 chars in under 90 mins. But, NTLM is a super fast hash type. I'm not recommending using brute force, but if there's a chance of a short password, you can do something like 

-a3 ?a?a?a?a?a?a?a --increment

And that will exhaust all the US keyboard characters in a 1-7 character password. Once you start going over that, it's going to take a long time.