Nmon
Nmon (Nigel's Monitor) is a system monitoring tool for Linux and AIX operating systems that provides real-time performance data in a command-line interface. It collects and displays metrics such as CPU usage, memory, disk I/O, network activity, and kernel statistics, helping administrators analyze system performance and identify bottlenecks. The tool can run in interactive mode for live monitoring or capture data to CSV files for later analysis.
Developers and system administrators should learn Nmon when they need to monitor and troubleshoot performance issues on Linux or AIX servers, particularly in production environments where resource utilization is critical. It is especially useful for diagnosing slow applications, capacity planning, and optimizing system configurations, as it offers detailed, low-overhead insights without requiring a graphical interface.