Terminating processes when exiting SSH

When working with git and a server via SSH, there’s a common headache: ssh-agent (or other processes) keep running in the background, even after you exit the console with exit. This leads to dozens of ssh-agent processes piling up… and most hosting providers have strict limits on the number of active processes. Not to mention, they just waste resources for no reason. And we’re all for efficiency, right?

So, here’s a quick recipe on how to automatically terminate ssh-agent on exit to avoid errors like:

error: cannot create thread: Resource temporarily unavailable
fatal: send-pack: unable to fork off sideband demultiplexer
-bash: fork: retry: Resource temporarily unavailable
-bash: fork: Resource temporarily unavailable

Alrighty… Normally, ssh-agent is launched with:

eval `ssh-agent -s` && ssh-add ./.ssh/

Of course, the right way to close it is manually (ssh-agent -k), but let’s be real – who remembers to do that?

The Fix:

I connect using this one-liner:

cd <your_domain_name>.com/public_html && eval `ssh-agent -s` && ssh-add ./.ssh/id_rsa && trap "ssh-agent -k" EXIT

What does this command do?

1. Moves to the website directory (cd <yourdomain>.ru/public_html).
2. Starts ssh-agent (eval `ssh-agent -s`).
3. Adds the SSH key (ssh-add ./.ssh/).
4. Sets up a trap that automatically terminates ssh-agent when exiting.
5. If you type exit, ssh-agent shuts down like a good boy!

For even more reliability, you can use:

cd <your_domain_name>.com/public_html && eval `ssh-agent -s` && ssh-add ./.ssh/id_rsa && trap "ssh-agent -k" HUP

EXIT terminates ssh-agent when you manually exit the shell with exit, whereas HUP also kills ssh-agent if the SSH connection is lost. So, if you forget to type exit and just close the window – everything cleans itself up automatically.

How to check if ssh-agent is still running?

ps aux | grep ssh-agent

If there’s no ssh-agent in the output, life is good.

If it’s still hanging around, forcefully terminate all greedy lingering ssh-agent processes:

pkill -9 ssh-agent

(Note that pkill -9 will kill all ssh-agent processes indiscriminately. If multiple users are on the server, this might terminate their ssh-agent too. To kill only your own:

pkill -u $USER ssh-agent)

Good lucks!