What this snippet does
The :- syntax supplies a fallback when the variable is unset or empty.
Expected output
myapp:latest on 0.0.0.0:3000
Why practise typing this
Typing compose advanced 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.
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