-c      Indicates that added identities should be subject to confirmation before being used for
        authentication.  Confirmation is performed by the SSH_ASKPASS program mentioned below.  Successful
        confirmation is signaled by a zero exit status from the SSH_ASKPASS program, rather than text
        entered into the requester.

-D      Deletes all identities from the agent.

-d      Instead of adding identities, removes identities from the agent.  If ssh-add has been run without
        arguments, the keys for the default identities will be removed.  Otherwise, the argument list will
        be interpreted as a list of paths to public key files and matching keys will be removed from the
        agent.  If no public key is found at a given path, ssh-add will append .pub and retry.

-e pkcs11
        Remove keys provided by the PKCS#11 shared library pkcs11.

-L      Lists public key parameters of all identities currently represented by the agent.

-l      Lists fingerprints of all identities currently represented by the agent.

-s pkcs11
        Add keys provided by the PKCS#11 shared library pkcs11.

-t life
        Set a maximum lifetime when adding identities to an agent.  The lifetime may be specified in
        seconds or in a time format specified in sshd_config(5).

-X      Unlock the agent.

-x      Lock the agent with a password.