Cheat Sheet
The commands you keep forgetting, with a one-line description and a real example you can copy - 384 across 26 tools. Pick a tool in the sidebar, or search across all of them.
Network Diagnostics
Diagnose connectivity, DNS, ports, and routes from the terminal.| Command | What it does | Example |
|---|---|---|
ping | Is the host reachable? | ping -c 4 google.com |
dig | DNS lookup. | dig example.com |
dig +short | DNS lookup, answer only. | dig +short example.com |
dig MX | Look up mail records. | dig MX example.com |
nslookup | DNS lookup (the classic). | nslookup example.com |
traceroute | Show the network path to a host. | traceroute google.com |
curl -I | Check an HTTP endpoint’s headers. | curl -I https://example.com |
ss -tulpn | Listening ports and the PIDs behind them. | ss -tulpn |
lsof -i :PORT | What process is using a port. | lsof -i :3000 |
nc -zv | Test whether a remote port is open. | nc -zv example.com 443 |
ip a | Show your network interfaces / IPs. | ip a |
ip route | Show the routing table. | ip route |
whois | Domain registration details. | whois example.com |