4.2. Directory based configuration
More flexible than the single configuration file is it to configure libpam via the contents of the
/etc/pam.d/ directory. In this case the directory is filled with files each of which has a filename equal to a service-name (in lower-case): it is the personal configuration file for the named service.
The syntax of each file in /etc/pam.d/ is similar to that of the
/etc/pam.conf file and is made up of lines of the following form:
type control module-path module-arguments
The only difference being that the service-name is not present. The service-name is of course the name of the given configuration file. For example,
/etc/pam.d/login contains the configuration for the login service.