What file is commonly used to configure user-related settings in Linux?

The file commonly used to configure user-related settings in Linux is /etc/passwd. This file serves a critical function in the Linux operating system as it contains essential information about each user account, such as the username, encrypted password (historically, though modern systems use /etc/shadow for more secure handling), user ID (UID), group ID (GID), user information, home directory, and the default shell. Each line in this file corresponds to a single user account, and the structured format facilitates straightforward parsing by system tools and commands.

Though other files are mentioned, they serve different purposes. For example, /etc/group manages group information, listing the various groups in the system and the users associated with them. /etc/shadow stores encrypted user password information with enhanced security measures, including additional fields for password aging and restrictions. /etc/users isn't a standard file in Linux, making it an incorrect choice. Thus, /etc/passwd is the definitive source for basic user configuration on a Linux system.