Overview
htop is an interactive process viewer for Linux. Combined with other CLI tools (top, vmstat, iostat, iotop, nethogs), it provides comprehensive real-time system monitoring without installing external agents.
Instructions
Step 1: Process Monitoring
bash
htop # interactive process viewer
htop -u deploy # filter by user
htop -p 1234,5678 # monitor specific PIDs
# Inside htop:
# F5 = tree view (parent/child processes)
# F6 = sort by column
# F9 = kill process
# / = search
# Space = tag process
Step 2: Resource Analysis
bash
# CPU and memory overview
free -h # memory usage (human-readable)
uptime # load average (1, 5, 15 min)
nproc # number of CPU cores
# Disk I/O
iostat -x 1 # disk I/O stats, 1 second interval
iotop # top for disk I/O (shows which process reads/writes)
# Network
nethogs # bandwidth per process
ss -tulnp # listening ports with process names
iftop # bandwidth per connection
Step 3: Quick Diagnostics Script
bash
#!/bin/bash
# scripts/server-status.sh — Quick health check
echo "=== CPU Load ==="
uptime
echo -e "\n=== Memory ==="
free -h
echo -e "\n=== Disk ==="
df -h /
echo -e "\n=== Top 5 CPU Processes ==="
ps aux --sort=-%cpu | head -6
echo -e "\n=== Top 5 Memory Processes ==="
ps aux --sort=-%mem | head -6
echo -e "\n=== Listening Ports ==="
ss -tulnp | grep LISTEN
Guidelines
- Load average > number of CPU cores = system is overloaded.
free -h: look at "available" column, not "free" (Linux uses free RAM for cache).- Use
dstatfor combined CPU/disk/net stats in one view. - For historical monitoring, pair with Prometheus + Grafana or Netdata.