TestOut Linux Pro Practice Test 2025 - Free Linux Pro Practice Questions and Study Guide

The command that can be used to check disk usage in Linux is "du," which stands for "disk usage." This command allows users to see how much disk space is being used by specific files and directories. When you run "du," it can give you a breakdown of space usage, helping you identify which files or directories are consuming the most disk space. This is particularly useful for system administration tasks, where managing disk space is crucial for maintaining system performance and preventing storage issues.

The "df" command, while also related to disk usage, provides information about the available and used space on mounted file systems in a more general sense rather than breaking it down by individual files and directories. The "free" command is used to display memory usage, including total, used, and free memory, while "space" is not a standard command in Linux. Therefore, "du" is the most appropriate choice for checking disk usage in detail.