Hello,
Try:
you@passbolt:/var/www/passbolt$ ./bin/cake passbolt register_user --help
Register a new user.
Usage:
cake passbolt register_user [options]
Options:
--first-name, -f The user first name
--help, -h Display this help.
--interactive, -i Enable interactive mode
--interactive-loop Enable interactive mode (default:3)
--last-name, -l The user last name
--quiet, -q Enable quiet output.
--role, -r The User role, such as "admin" or "user"
--username, -u The user email aka username
--verbose, -v Enable verbose output.