use keychain if available to automatically start ssh-agent

[SuperBFG7]

I tried to start the ssh-agent as a user service, but somehow the timing was off and it did not seem to start before the script tried to add the keys. So instead I added an option to use keychain, if installed.

Maybe you find this usefull.

In any case: thank you for the script, works perfectly for me with greetd, while pam_ssh did not.

cheers!
Daniel

[x70b1]

Yes, maybe if you start the agent after the login its slower than the pam-script. In my case the agent is always running and I restart them after logout, so that the system has no keys in the logged out state.

What would be the benefit of hash over if [ -f /usr/bin/keychain ... ?
With the test we wouldnt need to execute a binary.

[SuperBFG7]

I believe hash is a builtin command of bash. The benefit is, that it checks whether bash knows the command and does not assume its location or type (binary, alias, …). In this case the difference does probably not matter, I started to use it instead of test -f for all checks of executables.

I see shellcheck failed, will fix that tomorrow.

[x70b1]

$ type hash
hash is a shell builtin

cool! :)