Support multiple *.strings files in XCode project.
Using swift script to merge sub *.strings file into Localizable.strings.
Create your XCode project Copy scripts folder to your main project folder or modify script to point to script folder. Create main Localizable.strings file. Edit scheme Preaction and add sh command:
${PROJECT_DIR}/scripts/generateLocalizableFile.sh ${PROJECT_DIR}
Press cmd + B to trigger prebuild.
Switch to "Report Navigator" (cmd + 9) tab and select Top "Build" to see the output.