# crystal > Tool for managing Crystal source code. > More information: . - Run a Crystal file: `crystal {{path/to/file.cr}}` - Compile a file and all dependencies to a single executable: `crystal build {{path/to/file.cr}}` - Start a local interactive server for testing the language: `crystal play` - Create a project directory for a Crystal application: `crystal init app {{application_name}}` - Display all help options: `crystal help`