What file format is primarily used in Linux to store user account settings?

The primary file format used in Linux to store user account settings is a text file. Specifically, user account information is typically stored in plain text format within files like /etc/passwd. This file contains essential details about each user, such as the username, encrypted password, user ID, group ID, and other related information. The simplicity of a text file allows for easy reading and editing using standard command-line tools, which is especially beneficial for system administrators.

In contrast, other formats like CSV, XML, and JSON are often used for different purposes in various applications but are not standard for user account information in Linux. CSV is commonly used for spreadsheet data, XML is frequently used for configuration files or data interchange, and JSON is popular in web applications for data serialization. However, these formats do not serve the typical role of storing user account settings in a Linux environment.