How to find the last n characters of a password

[lalalalala12345]

Completely new, no experience with this tool.

I have a 12 character password for which I know the SHA1 hash and the first 7 characters.
How would I go about finding the rest of the password? I don't wish to use any word sets, just a straightforward brute force to find the last 5 characters.

[penguinkeeper]

Command:
hashcat -m 100 YourHash -a 3 FIRST7C?a?a?a?a?a
Just replace "YourHash" of course with your hash and "FIRST7C" with the first 7 known characters. Hashcat should output "Status.....: Cracked" if it cracked your password and show your hash and the hash:plaintext above that

[lalalalala12345]

Command:
hashcat -m 100 YourHash -a 3 FIRST7C?a?a?a?a?a
Just replace "YourHash" of course with your hash and "FIRST7C" with the first 7 known characters. Hashcat should output "Status.....: Cracked" if it cracked your password and show your hash and the hash:plaintext above that

Thanks