Page

$ unshadow passwd-file.txt shadow-file.txt > unshadowed.txt
$ john --rules --wordlist=wordlist.txt unshadowed.txt

Just shadow

$ echo '$6$Tb/euwmK$OXA.dwMeOAcopwBl68boTG5zi65wIHsc84OWAIye5VITLLtVl aXvRDJXET..it8r.jbrlpfZeMdwD3B0fGxJI0' > hash.txt'
$ john --format=sha512crypt --wordlist=/usr/share/wordlists/rockyou.txt hash.txt