ARG defines a variable that users can pass at build-time to the builder with the docker build command using the --build-arg
ARG user1 # Defines an build argument called 'user1' without any default values ARG buildno # Defines an build argument called 'buildno' without any default values ARG user1=someuser # Defines and declares a default value for the build argument 'user1' ARG buildno=123 # Defines and declares a default value for the build argument 'buildno'