fastlane:tldr:59f65

The fastlane run build_app command is used in the Fastlane tool to build an app. Fastlane is a command-line tool used for automating the build, testing, and deployment of iOS and Android apps.

When you execute fastlane run build_app, Fastlane will execute the defined build lane, which typically includes multiple steps involved in building the app. These steps might include tasks such as setting environment variables, running tests, generating code signing certificates, and packaging the app for distribution.

The exact behavior of the build_app command depends on the configuration defined in your Fastfile. The Fastfile is a configuration file where you define lanes – sequences of steps – to perform various tasks in your app's development lifecycle.

By running fastlane run build_app, you are instructing Fastlane to execute the lane responsible for building your app based on your specified configuration, ensuring consistency and repeatability in the build process.