removing keys from ssh-agent without having key file

[Damien Miller]

On Fri, 1 Jan 2016, Matthew Boedicker wrote:

> ssh-agent does not allow you to remove individual keys without having the
> key file that was added. To remove these keys the user must remove all keys
> with ssh-add -D.

No, you only need the public key and you can get that from the agent
itself if you don't happen to have it laying around.

[djm at fuyu tmp]$ ssh-keygen -q -t ed25519 -f k1 -N '' 
[djm at fuyu tmp]$ ssh-keygen -q -t ed25519 -f k2 -N '' 
[djm at fuyu tmp]$ ssh-add k1 k2
Identity added: k1 (djm at fuyu.mindrot.org)
Identity added: k2 (djm at fuyu.mindrot.org)
[djm at fuyu tmp]$ ssh-add -L
ssh-ed25519 AAAAC3NzaC1lZDI1NTE5AAAAIKJmyuVthrSvC6RMly/gJyAd1oFo8NggUUAV0JKvW9V4 djm at fuyu.mindrot.org
ssh-ed25519 AAAAC3NzaC1lZDI1NTE5AAAAIFk1eV8abvdBGAJINxDZ2fK9btsLUlHmPL9DPBDhh/MP djm at fuyu.mindrot.org
[djm at fuyu tmp]$ rm k1* k2*
[djm at fuyu tmp]$ ssh-add -L | head -1 > k1.pub
[djm at fuyu tmp]$ ssh-add -d k1 
Identity removed: k1 (djm at fuyu.mindrot.org)
[djm at fuyu tmp]$ ssh-add -L
ssh-ed25519 AAAAC3NzaC1lZDI1NTE5AAAAIFk1eV8abvdBGAJINxDZ2fK9btsLUlHmPL9DPBDhh/MP djm at fuyu.mindrot.org

-d