Quote:
=================================================....
~/.ssh/identity.pub
~/.ssh/id_dsa.pub
~/.ssh/id_rsa.pub
Contains the public key for authentication. These files are not
sensitive and can (but need not) be readable by anyone. They are
never used automatically and are not necessary: they are only
provided for the convenience of the user.
....
=================================================
The phrase "They are never used automatically ..." is incorrect.
The ssh client automatically read .pub file for specified identities,
send public keys to server and when key is accepted then ssh read
private key, might ask user for password and send signed user
authentication request.
If the .pub file don't exist ssh will read private key, might ask user
for password, send it to the server and when key is accepted then ssh
will use it in actual authentication.
Test command: ssh -vvv -i id_dsa ....
Remove the file id_dsa.pub and run command again.
Compare output in both cases.
The command ssh-add use pub file to delete key from agent.
Test to delete key form agent with and wihtout pub file.
Regards,
Roumen