我有几个旧的 ssh 密钥，~/.gnupg/sshcontrol所以我删除了这个文件中的所有行并重新启动了我的计算机。现在，我不能再向 gpg 代理添加 ssh 密钥了：
$ cat ~/.gnupg/gpg-agent.conf
enable-ssh-support
$ gpg-connect-agent --verbose /bye
gpg-connect-agent: closing connection to agent
$ gpg-connect-agent updatestartuptty /bye
OK
$ ssh-add -l
The agent has no identities.
$ ssh-add ~/.ssh/id_rsa
Enter passphrase for /home/cassou/.ssh/id_rsa:
Identity added: /home/cassou/.ssh/id_rsa (/home/cassou/.ssh/id_rsa)
$ ssh-add -l
The agent has no identities.