I am now in school for learning more about IT Security.
How we now can defeat the security problems like not using username and passwords only for logging in.
And more using 2FA or using some kind of hardware token like Yubikey.
Now we have some lab's to do, and using tools like john.
And just run that command spits out some usage: like this.
John the Ripper password cracker, version 1.8.0
Copyright (c) 1996-2013 by Solar Designer
Homepage:
http://www.openwall.com/john/Usage: john [OPTIONS] [PASSWORD-FILES]
--single "single crack" mode
--wordlist=FILE --stdin wordlist mode, read words from FILE or stdin
--rules enable word mangling rules for wordlist mode
--incremental[=MODE] "incremental" mode [using section MODE]
And then just try to load the man page with same program spits out.
OPTIONS
All the options recognized by john start with a single dash (`-'). A summary of options is included below.
-external:MODE
Enables an external mode, using external functions defined in ~/john.ini's [List.External:MODE] section.
-format:NAME
Allows you to override the ciphertext format detection. Currently, valid format names are DES, BSDI, MD5, BF, AFS, LM.
And now to the first line in the options section, says only single dash.
And now see how many you need to provide when just running the command...., two dash or single dash (like hamlet to be or not to be)