U did it and now u regret

And now u want them back.

No more starting approx. 1 grabillion ssh-agent processes -- just pick up where u left off.

What it does

U open a new terminal. Ur keys are gone. Not gone gone -- the ssh-agent u started three terminals ago is still sitting there holding them, u just forgot where u put it.

This script goes and finds it:

• Already got a working agent? (forwarded with ssh -A, ur desktop keyring, etc.) Then u didn't lose anything. It does nothing. Go away.
• Otherwise it looks for agent sockets in $TMPDIR (or /tmp) as ssh-*/agent.*, and in ~/.ssh/agent/ where newer OpenSSH hides them, newest first.
• Only ur sockets. Not ur coworker's. We are not that kind of script.
• Only live ones. Dead sockets from agents that died in the line of duty get skipped.
• Found one? SSH_AUTH_SOCK gets pointed at it. SSH_AGENT_PID gets set too if it can tell which agent that is (it only matters for ssh-agent -k, so it won't guess).
• Found nothing? It leaves ur environment alone instead of making stuff up. Start an agent like a normal person: eval "$(ssh-agent -s)".

It's plain POSIX sh, so it works in sh/dash, bash and zsh, and it cleans up its own variables so ur shell doesn't fill up with junk.

Install

This file gets sourced, not run. Running it does nothing useful -- the exports die with the subshell, just like ur hopes.

Just for u (recommended)

cp u_lost_yr_keys.sh ~/.u_lost_yr_keys.sh
echo '. ~/.u_lost_yr_keys.sh' >> ~/.bashrc   # or ~/.zshrc, or ~/.profile

~/.bashrc runs in every new terminal. /etc/profile.d only runs in login shells, and plenty of terminal emulators don't start those.

For everyone on the box

sudo cp u_lost_yr_keys.sh /etc/profile.d/

Every user's login shells pick it up. It only ever grabs each user's own agent, so it's not going to hand ur keys to anyone. (zsh doesn't read /etc/profile.d by default. Not our fault.)

Try it

eval "$(ssh-agent -s)" && ssh-add          # start an agent, add a key
env -u SSH_AUTH_SOCK -u SSH_AGENT_PID sh   # new shell, keys "lost"
. ./u_lost_yr_keys.sh                      # ...found
ssh-add -l                                 # there they are

Or just never lose them

If u'd rather not lose them in the first place, give the agent a fixed address (ssh-agent -a ~/.ssh/agent.sock), or use keychain, or ur distro's systemd user ssh-agent service. We won't be offended. Much.