1. An OpenSSH key manager Keychain is an OpenSSH key manager, typically run from ~/.bash_profile. When run, it will make sure ssh-agent is running; if not, it will start ssh-agent. It will redirect ssh-agent's output to ~/.ssh-agent, so that cron jobs that need to use ssh-agent keys can simply source this file and make the necessary passwordless ssh connections. In addition, when keychain runs, it will check with ssh-agent and make sure that the ssh RSA/DSA keys that you specified on the keychain command line have actually been added to ssh-agent. If not, you are prompted for the appropriate passphrases so that they can be added by keychain. From Debian 3.0r0 APT