Resource monitoring in Linux

CPU Memory usage

1. top – Real-time system summary.

2. htop:- Interactive process viewer (advanced top).

3. vmstat :- System memory, processes, paging, etc.

4. free -h :- Memory usage in human-readable format.

5. mpstat :- CPU usage (install via sysstat package).

6. iostat :- CPU and disk I/O (also from sysstat).

7. uptime :- How long the system has been running.

8. lscpu :- CPU architecture info.

9. numactl —hardware – NUMA node memory info.

10. sar :- Collects, reports system activity (install sysstat).

Disk Usage and I/O

11. df -h:- Disk space usage.

12. du -sh :- Directory size

13. lsblk :- List block devices.

14. mount :- Mounted filesystems.

15. findmnt :- Show mounted filesystems in tree.

16. iostat :- Disk I/O statistics.

17. iotop :- Real-time disk I/O. (need to use by super user)

18. blktrace :- Trace block I/O.

dstat :- Versatile resource statistics.

Process and Services

1. ps aux – List all running processes.

2. pidstat – Process-level resource usage.

3. systemctl status – Check service status.

4. service – Manage system services (older systems).

Example of service command is like:- sudo service ssh status

5. watch – Run commands repeatedly
   example :- watch [options] <Command> like:- watch df -h

Network Monitoring

1. ip a – Show IP addresses.

2. ss -tuln – Show listening ports.

3. netstat -tulnp – (Old but still used).

4. iftop – Real-time bandwidth monitor.

5. nethogs – Bandwidth per process.

6. traceroute – Trace network path

• It maps the route packets take to reach a host.

• Helps identify network delays or where a connection is failing.

• Each line in the output = a router/hop between your system and the target.

7. ping – Check network reachability.

8. dig or nslookup – DNS lookup.

File and Log Monitoring

1. tail -f /var/log/syslog – Real-time log monitoring.

2. journalctl -xe – View systemd logs.

3. lsof – List open files.

4. inotifywait – Watch for file changes.

5. stat – Detailed file info.
   command :- stat <filename>

Hardware Info

1. lshw – List hardware info.

2. lsusb – USB devices.

3. lspci – PCI devices.

4. dmidecode – BIOS/firmware info.

5. sensors – Hardware temperature sensors.

General System Info

1. uname -a – Kernel and system info

2. hostnamectl – Host and OS details.

3. dmesg | less – Kernel messages.