1. Create and add a Gatekeeper label to the app. (‘Approved’ is an arbitrary string.)

        spctl --add --label "Approved" /path/to/xyz.app

2. Approve all apps with the label.

        spctl --enable --label "Approved"

   This only needs to be done once and adding the same named label to apps in the future automatically enables their access.

3. Open the app as usual.

        open xyz.app

For more information about spctl (SecAssessment system policy security), see the man page.