Using a free product like KIWI CATtools, you can take backups of the system config of up to 20 devices (free version), including the ASA, routers, and switches. It will take backups of the configs and store with e date stamp so you have some nice change control and historicals of the different configs.
Try the following from CLI
copy startup tftp
You need a tftp server!
Best regards,
Istvan