Top 20 Linux Monitoring Tools Every Sysadmin Should Know

As the internet industry evolves, countless monitoring tools have emerged. This curated list presents over twenty Linux utilities for managing machines, covering command‑line tools, network‑related monitoring, system monitoring, log monitoring, and infrastructure monitoring.

System Monitoring Tools

1. top

This small utility, pre‑installed on many UNIX systems, provides a real‑time view of processes and threads, defaulting to CPU‑based sorting.

2. htop

An enhanced, interactive version of top that offers easier sorting and a more intuitive display.

3. powertop

Helps diagnose power consumption and power‑management issues, allowing configuration for optimal server efficiency.

4. iotop

Displays I/O usage per process with a top‑like interface, showing read/write rates and the percentage of time a process spends waiting for I/O.

Network‑Related Monitoring

5. ntopng

An upgraded version of ntop that provides a web‑based GUI for network monitoring, host geolocation, traffic analysis, and IP flow distribution.

6. iftop

Similar to top but focuses on network interface traffic, presenting current usage in a table format.

7. bandwidthd

Tracks TCP/IP subnet usage and visualizes it as PNG images in a web page, supporting databases, sensors, and custom reports.

8. NetHogs

Groups network traffic by process rather than by protocol or subnet, helping identify which process causes traffic spikes.

9. ngrep

A "grep" for network packets, using pcap and allowing regex or hex pattern matching.

10. traceroute

Displays the route and measures latency of packets across the network.

11. ss

Provides more detailed and faster socket statistics than netstat; use ss -s for a summary.

12. nmap

Scans open ports, detects operating systems, and can be used for vulnerability assessment, network discovery, and penetration testing.

13. Tcpdump

Captures packets matching a given expression and can save them for further analysis.

System‑Related Monitoring

14. Dstat

Replaces vmstat, iostat, netstat, and ifstat, providing real‑time resource statistics with CSV export and plugin support.

15. vmstat

Shows virtual memory statistics and overall memory usage.

16. pmap

Reports a process's memory map, helping locate memory bottlenecks.

Log Monitoring Tools

17. GoAccess

A real‑time web log analyzer for Apache, Nginx, and CloudFront, exporting results as HTML, JSON, or CSV and providing basic statistics, 404 counts, visitor locations, etc.

System Tools

18. strace

Diagnoses and monitors system calls of programs, showing the sequence of calls made during execution.

19. lsof

Lists open files and network connections, indicating which process opened each file.

Infrastructure Monitoring Tools

20. Nagios

Monitors multiple servers and services, providing alerting and a plugin ecosystem.

21. Cacti

A network graphing solution using RRDtool, supporting polling, scripting extensions, and customizable reports.

22. Zabbix

An open‑source infrastructure monitoring platform written in C with a PHP front‑end, offering agent‑less deployment options.

Source: http://www.codeceo.com/article/80-more-linux-monitor-tools.html