Duvdevan Duvdevan - 10 months ago 74
Bash Question

How to check if ssh-agent is already running in bash?

I have a sample

sh
script on my Linux environment, which basically run's the
ssh-agent
for the current shell, adds a key to it and runs two git commands:

#!/bin/bash
eval "$(ssh-agent -s)"
ssh-add /home/duvdevan/.ssh/id_rsa

git -C /var/www/duvdevan/ reset --hard origin/master
git -C /var/www/duvdevan/ pull origin master


Script actually works fine, but every time I run it I get a new process so I think it might become a performance issue and I might end up having useless processes out there.

An example of the output:

Agent pid 12109
Identity added: /home/duvdevan/.ssh/custom_rsa (rsa w/o comment)


Also, along with all this, is it possible to find an existing
ssh-agent
process and add my keys into it?

Answer Source

If you want it to be killed right after the script exits, you can just add this after the eval line:

trap "kill $SSH_AGENT_PID" exit

Or:

trap "ssh-agent -k" exit

$SSH_AGENT_PID gets set in the eval of ssh-agent -s.

You should be able to find running ssh-agents by scanning through /tmp/ssh-* and reconstruct the SSH_AGENT variables from it (SSH_AUTH_SOCK and SSH_AGENT_PID).