CompTIA Linux+ Certification Practice Exam 2025 - Free Linux+ Practice Questions and Study Guide

The command that is used to display CPU usage statistics is sar. Short for "System Activity Reporter", sar is part of the sysstat package and is utilized to collect and report system activity information, including CPU utilization. When executed, sar can provide a variety of metrics, such as the percentage of CPU usage that is user time, system time, idle time, and more. This makes it a powerful tool for analyzing CPU performance over specific intervals, allowing administrators to make informed decisions about system optimization and resource allocation.

While mpstat also provides CPU usage statistics, it focuses on individual processors or sets of processors, rather than providing a comprehensive view of system-level statistics over time. iostat, on the other hand, is designed to display input/output statistics for devices and partitions, primarily focusing on I/O performance rather than CPU usage. The free command is used to display information about system memory usage and does not pertain to CPU statistics at all, further differentiating it from the correct choice.