Can I check a configuration file without restarting AMPS?

Yes!

The ampServer binary includes a --verify-config flag that will parse and validate the configuration without starting AMPS.

This flag does the same verification that AMPS does when it starts.

Notice that this verification will report "Address already in use." errors if there is an existing AMPS instance using that port on the system (including an instance that uses the configuration file being validated).