johntheripper mini howto

cracking passwords

simple crack on single user "admin" in password file using default john word list and settings

# john --users=admin --session=mycrack /etc/passwd

the password file must include the password hashes

crack status

# john --status=mycrack

shadow files

if the system you are trying to crack passwords on uses the /etc/shadow file to store password hashes (very likely), then use john's unshadow utility to construct / consolidate the /etc/passwd and /etc/shadow into one file for cracking

example

# unshadow /etc/passwd /etc/shadow > /var/tmp/passwd-shadow