Where is user account information stored in a Linux system?

User account information in a Linux system is primarily stored in the /etc/passwd file. This file contains essential details about each user account, including the username, user ID (UID), group ID (GID), user information (full name or comment), home directory, and the default shell that the user will use upon login. Each entry in the /etc/passwd file is structured in a specific format, making it easy for the system to read and process this information when user accounts are accessed.

While /etc/shadow holds encrypted passwords and related account information for security purposes, and /etc/group contains group membership information, the /etc/passwd file is the foundational file that outlines the core details of user accounts. Meanwhile, /var/log/auth.log is used to track authentication events and logging information but does not store user account details.

Having a proper understanding of these files is crucial for system administration, as they play different roles in user account management and system security. The structure and permissions of these files are also important for ensuring that user data is protected from unauthorized access.