What this snippet does
ENV values persist into the running container and are visible to every process it starts.
Expected output
production
Why practise typing this
Typing env & arg code builds muscle memory for the symbols and indentation Docker uses most, which prose-based typing tests never cover. DevType measures your words per minute and accuracy on this snippet and tracks the individual characters you mistype, so later lessons can target them.
More Docker practice
- Multiple values in one layerENV & ARG · beginner
- Build-time argumentENV & ARG · intermediate
- ARG is gone at runtimeENV & ARG · intermediate
- ARG before FROM has limited scopeENV & ARG · advanced
- Parameterised base imageENV & ARG · advanced
- Secrets leak through build argsENV & ARG · advanced