SSH config: type “ssh prod” instead of an IP address and flags

The command ssh -p 2222 jan.novak@203.0.113.42 -i ~/.ssh/company_key is exactly the kind of thing nobody remembers — so it ends up living in a notes app, copy-pasted with the mouse. Yet SSH has an elegant built-in solution: the config file ~/.ssh/config, where you write down the address, username, port, and key path once under a short name. From then on you just type ssh prod — and the same shortcut works in scp, rsync, and in VS Code's remote development too.

How to do it

1. Open (or create) the file ~/.ssh/config — a plain text file that works on Mac, Linux, and Windows with OpenSSH.

2. Add an entry for the server:

   Host prod
       HostName 203.0.113.42
       User jan.novak
       Port 2222
       IdentityFile ~/.ssh/company_key
   

   Copy

3. Save it and connect: ssh prod. SSH fills in all the details itself. Lines you don't need (default port 22, a single key) can be left out.

4. Add as many entries as you like — prod, test, nas, school. These names then show up in tab completion too, and work everywhere SSH is used: scp backup.tar.gz prod:/opt/, rsync -av web/ prod:/var/www/, a remote window in VS Code.

5. Write settings shared by every server under Host * — for example ServerAliveInterval 60, which sends keep-alive packets so idle connections don't drop.

A typical scenario

A developer manages six servers — two at a client with a nonstandard port, three company machines, and a home NAS, each with a different username. She used to fish the exact combination out of her notes for every connection, and would coach coworkers over the phone: “no, it's admin there, not deploy.” Now she has six entries in her config and connects with ssh client-web, ssh nas. When a server's IP address changes, she fixes it in one place — and every one of her commands, scripts, and saved VS Code connections keep working without a single change.

The config handles more advanced situations too: a server hidden behind a jump host is solved with the line ProxyJump gateway (SSH connects to the gateway first and tunnels through it, with no extra effort on your part), and when you need a different key for GitHub than for work, you assign it with an entry under Host github.com. All declarative, in one place, in a readable text file.

What you get out of it

Connecting to any server becomes two words off the top of your head instead of copy-pasting from notes. Server names become part of your muscle memory, while a single file handles the addresses, ports, and keys correctly, every time. Combined with the tip on ssh-copy-id — a key instead of a password, a name instead of an address — a remote server is suddenly as close as your local terminal.