My Ionic info:
cli packages: (/usr/lib/node_modules) @ionic/cli-utils : 1.9.2 ionic (Ionic CLI) : 3.9.2 global packages: Cordova CLI : 7.0.1 local pack
In ionic 3 you have to type:
cordova run android or cordova run ios, to deploy your build in device.
cordova run android
cordova run ios
cordova build android or cordova build ios, for build only.
cordova build android
cordova build ios