ssh-locate

A command line tool that helps you locate and contact a SSH agent launched in a separate shell.

Wait, what ⁉️

This tool fills a gap in the OpenSSH suite of tools.

• No way of knowing the PID of a running SSH Agent
• No way of knowing the authentication socket of a running SSH Agent
• ssh-agent only supports Bourne and C shells

Features

• output is fully compatible with openSSH:

    SSH_AUTH_SOCK=/tmp/ssh-locate-test.15970; export SSH_AUTH_SOCK;
    SSH_AGENT_PID=12427; export SSH_AGENT_PID;
    echo Agent pid 12427;

• supports the Fish shell

set -x SSH_AUTH_SOCK ssh-agent -a /tmp/zed
set -x SSH_AGENT_PID 1517651

(See also Fish Startup below)

• shows EMACS Lisp to activate agent:

(setenv "SSH_AUTH_SOCK" "/tmp/zed")
(setenv "SSH_AGENT_PID" "3216002")

Installation

gem install ssh-locate

Usage

Launch your SSH agent and tell it to use a specific socket file with the -a option:

ssh-agent -a /tmp/deployer-38us9f

In a later shell (or any process running for the user who owns the agent):

Bash

$ eval `ssh-locate`
Agent pid 13457

Fish

> ssh-locate | source

EMACS

Using the --emacs option will output the lisp code to set the necessary environment variables in EMACS. Just paste this anywhere (in a scratch buffer for example) and execute eval-last-sexp (usually bound to C-x C-e) with the cursor positionned at the end of each line.

ssh-locate --emacs

Fish startup

You can launch and activate an agent at startup by adding this to your config.fish:

ssh-agent -a /tmp/arnaud
ssh-locate | source

Caveat

ssh-locate only reports the first agent found in the process table. If you have a scenario where you would like to be more specific, let me known and I can extend the selectivity. I just do not need that right now.

TODO

As the YAGNI wisdom tells us not to fantasize requirements, here are some potentially useful things that are not implemented yet:

• Be aware of the agent launched by Ubuntu
• Have a more sensible output if no agent was found