When configuring OpenLDAP with PAM and NSS, which parameter completes this line from /etc/nsswitch.conf: passwd files _____?

The parameter that completes the line from /etc/nsswitch.conf as "passwd files _____" is "ldap." This line is part of the Name Service Switch configuration, which determines the sources from which the system retrieves user and group information. In this context, when configuring OpenLDAP with the Pluggable Authentication Module (PAM) and the Name Service Switch (NSS), the "ldap" entry indicates that the system should query an LDAP directory for user account information in addition to traditional files like /etc/passwd.

In a mixed environment with LDAP, the "ldap" entry allows for centralized user management, granting users access to network resources and services through LDAP. Utilizing "ldap" here ensures that when a user queries for password information, the system will first check local files and then, if the user is not found there, it will check the LDAP directory service. This cascading approach provides flexibility and scalability in user account management.

Other options such as "pam," "pam_nss," and "pam_ldap" do not fit within this specific context, as they refer to different components of the authentication stack rather than the information sources defined in the nsswitch.conf file.