Ryfujk

I'm trying to create a shell script that, among other things, starts up ssh-agent and adds a private key to the agent. Example:

#!/bin/bash

# ...

ssh-agent $SHELL

ssh-add /path/to/key

# ...

The problem with this is ssh-agent apparently kicks off another instance of $SHELL (in my case, bash) and from the script's perspective it's executed everything and ssh-add and anything below it is never run.

How can I run ssh-agent from my shell script and keep it moving on down the list of commands?

ssh-agent is supposed to start a session and when it finishes the user session is over. So any command after ssh-agent would perhaps be executed after logoff.

What you want is a session-script that contains your sessions commands like this:

#!/bin/bash

ssh-add /path/to/key

bash -i # or other session starter

Then start ssh-agent session-script.

Put the following at the top of your script:

eval `ssh-agent`

Your script should look like this:

#!/bin/bash

eval `ssh-agent`

ssh-add /path/to/key

...

...

Explanation

The backticks around ssh-agent collect its output. eval collects that output, concatenates it into a single command, and then executes the command. Then you can use ssh-add to provide your key credentials.

I tend to do something like this in scripts that require an agent.

#!/bin/bash



# if we can't find an agent, start one, and restart the script.

if [ -z "$SSH_AUTH_SOCK" ] ; then

  exec ssh-agent bash -c "ssh-add ; $0"

  exit

fi



... and so on.

Basically the first thing the script does it check to see if an agent is running. If it isn't exec is used to start a new process in place of the script. The agent is started, keys are added, and finally, the script is called again (see the $0).

It is better to use keychain in this case

Debian/Ubuntu:

apt-get install keychain

RHEL/Fedora/CentOS

yum install keychain

Add in your .bashrc the following:

eval `keychain --eval id_rsa`

I found this works for me.

eval `ssh-agent` # create the process

ssh-add ~/.ssh/priv_key # add the key

git -C $repo_dir pull # this line is the reason for the ssh-agent

eval `ssh-agent -k` # kill the process

I create the ssh-agent process, add the key, do what I need to do, then kill it. No need to check if it's running later.

I found with Zoredache's solution, the key would be available to any shell that happens to share the same ssh-agent as the shell that called the script. I wanted to avoid this in a script that required root access to a remote machine, for obvious security reasons.

I've found putting the following shebang at the top of the script works:

#!/usr/bin/ssh-agent bash



ssh-add /path/to/ssh-key

ssh root@remotehost "remote commands"

None of these solutions worked aparently for me.
I tried multiple variations of the solutions provided by the experts above.

#!/usr/bin/ssh-agent bash

#

# if we can't find an agent, start one, and restart the script.

#       if [ -z "$SSH_AUTH_SOCK" ] ; then

#               exec ssh-agent bash -c "ssh-add /home/username/.ssh/user_rsa ; $0"

#               exit

#       fi

#eval `ssh-agent`

ssh-add /home/username/.ssh/user_rsa

ssh-add -l

However I if I just run these commands manually, it works for me. wondering what is going wrong here.

eval `ssh-agent`

ssh-add /home/username/.ssh/user_rsa

ssh-add -l

appreciate any help you can offer.