You've linked into it, but I was just going to point at the Git book: https://git-scm.com/book/en/v2

It's an afternoon's reading; it does an excellent job of giving you the right mental model - and a crib aheet of commands to navigate it.

"Maybe our friend doesn't like monads."

Netware was rock solid.

Minimise your windows one at a time and check that the gnome keyring hasn't popped up a dialog box sonewhere behind everything else that's asking you if it's okay to proceed.

It's the gnome key ring ssh agent.

It's possible that this has popped up a window asking gor permission / a passphrase / something and you're not seeing that.

That's only part of the handshake. It'd require agent input around that point.

Is this problem a recurring one after a reboot?

If it is it warrants more effort.

If not and you're happy with rhe lack of closure, you can potentially fix this: kill the old agent (watch out to see if it respawns; if it does and that works, fine). If it doesn't, you can (a) remove the socket file (b) launch ssh-agent with the righr flag (-a $SSH_AGENT_SOCK iirc) to listen at the same place, then future terminal sessions that inherit the env var will still look in the right place. Unsatisfactory but it'll get you going again.

Okay, that agent process is running but it looks wedged: multiple connections to the socket seem to be opened, probably your other attempts to use ssh.

The ssh-add output looks like it's responding a bit, however.

I'd use your package manager to work out what owns it and go looking for open bugs in the tool.

(Getting a trace of that process itself would be handy, while you're trying again. There may be a clue in its behaviour.)

The server reaponse seems like the handshake process is close to completing. It's not immediately clear what's up there I'm afraid.

Please don't ignore the advice about SSH_AGENT_SOCK. It'll tell yoy what's going on (but not why).

Without the ssh-agent invocation:

• what does ssh-add -L show?
• what is the original SSH_AUTH_SOCK value?
• what is listening to that? (Use lsof)

This kind of stuff often happens because there's a ton of terrible advice online about managing ssh-agent - make sure there's none if that baked into your shellrc.

Experience. For what it's worth, the instinct I distrust is absolutism.

I think it's like the distinction between art and obscenity; it's not a nuanced distinction in the case in question. If it were, I'd largely trust UK courts to get it right (they are by-and-large capable of this, and much less politicised than their US counterparts).