Using environment variables as dynamic keys

[mudideng]

Hi! In yq v3, I used to be able to do set values to keys dynamically, something like

yq write --inplace \
              "${SOME_FILE}" \
              "animals.${FAMILY}" \
              "${SPECIES}"

Is this still possible with yq v4? I couldn't figure out a way to do it. The env() operator only seems to work for setting the value when I tested it.

[mikefarah]

Yep, you can do it using interpolation in your shell like you've done, or via the env operator documented here: https://mikefarah.gitbook.io/yq/operators/env-variable-operators#dynamic-key-lookup-with-environment-variable

Env operator is useful just because it sidesteps escaping and quoting issues in shells

[mudideng]

Thanks for the answer! Kinda embarrassing that I searched for dynamic keys and still didn't find it when it's right there in the documentation...

And indeed, maybe I should use the env operator, since the issue I had was because of quoting issues. Thanks again!