Diagnosing between two machines

Articles

• Output redirection and pipelines — A shell instruction that connects a command's stream to a file or another descriptor: > overwrites a file, >> appends, < reads from a file, and 2>&1 sends stderr wherever stdout goes.
• Network diagnostics — A ladder of connectivity checks — from the gateway to DNS and the destination port.
• ip — addresses, interfaces and routes — Manage interfaces, addresses and routes (iproute2) — the replacement for ifconfig/route.
• ssh, scp — connecting and copying over SSH — A client for logging in and copying files over SSH; host aliases in ~/.ssh/config remove repeated connection parameters.
• curl — HTTP requests from the console — curl sends HTTP and HTTPS requests from the console: status code, headers, the whole exchange, certificate checks.