COmanage Registry uses a shell command to facilitate certain automatic processing. To enable this, it is recommended that the shell command be run periodically from cron. (The shell command can also be run manually if needed.)
The cron command should look something like this:
0 1 * * * cd /path/to/registry-source/app && Console/cake cron
This will run automatic processing every morning at 1am.
Currently, the only supported functionality is to automatically execute Expiration Policies. As such, once per day should be sufficient, to cover expirations driven by valid through dates. 
This recommendation may change in a future release.
The cron command should run as the web server user in order to avoid problems with file permissions.
See also: Running Shells as cronjobs