RANCID, the Really Awesome New Cisco confIg Differ Rancid maintains CVS controlled copies of router (device) configurations. I uses expect to login to a list of devices and collect their software configuration, hardware information, etc. The collected data is formatted, trimmed, etc. Each is diff(1)'d against the previous and the output is e-mailed to a mail list, then committed to the cvs repository. It supports various Cisco routers & switches, Juniper Networks routers, and several others. Besides being useful for tracking configuration changes, Rancid comes with several scripts that are generally useful for network management, including the expect scripts that automate device logins.