I am trying to create a script that adds my SSH private key to ssh-agent.

 #!/bin/bash

 ssh-agent /bin/sh 
 ssh-add passphrase_encrypted_key

If I run these commands from the command line, I am prompted for the passphrase after the ssh-add command. If I run them as a script, I'm never prompted for a passphrase.

I know this has something to do with subprocessing and/or a sub-shell being created, but I just can't find the information that points me in the right direction.

I have tried commands, "set -m", exec, placing the command in left right parenthesis and maybe a few others that I can't think of right now.

For any response that I receive, a good reference on understanding the fundamentals on how bash scripting works with sub-processes, etc. would really help.

FYI, the ssh-agent is not started by default on the machine that I am using and I am not the admin.

CodePudding user response：

After much more research, I was able to figure out that I needed to add the following line to my script:

eval "$(ssh-agent -s)"

I don't understand why I need the $, because I thought that was only for referencing variables defined within the shell script, so I have more research to do.

My final basic script looks like:

#!/bin/bash

eval "$(ssh-agent -s)" 
ssh-add passphrase_encrypted_key

After the script executes the line which adds the key to the agent, I'm prompted for the passphrase as expected.

Thank you to everyone that has responded.