A PAM Config File

Here is /etc/security/halt:
auth       sufficient   /lib/security/pam_rootok.so
auth       required     /lib/security/pam_console.so
auth       required     /lib/security/pam_pwdb.so
account    required     /lib/security/pam_permit.so

Each line contains the following fields:

Module type - one of 'auth', 'account', 'password' or 'session'.

Control flag - one of 'required', 'requisite', 'sufficient' or 'optional'.

Module path - full path to the module's dynamic library (full path or relative to "/lib/security").

Arguments - module-specific parameters.