npm run ios some time an error comes
$ react-native-scripts ios
Unable to check Xcode version: Error: Process exited with non-zero code: 1
Failed to start simulator:
Unable to verify Xcode and Simulator installation.
The error can come if you don’t have any command line tool selected in xcode .To resolve the issue go to
Xcode->preferences -> Locations-> command line tools and select the command line tool as shown in image below.