Configurations can be overridden by specifying NODE_CONFIG='{...}' command line parameter when starting your application.

The parameter value must be supplied as a valid JSON string. The following example overrides the Customer.dbConfig.host configuration:

$ NODE_CONFIG='{"Customer":{"dbConfig":{"host":"customerdb.prod"}}}' node myapp.js 

The single quotes around the JSON value preserve the double quotes, and you may have to escape special characters, based on your O/S shell.

The NODE_CONFIG parameter may also be supplied as a shell environment variable