yq/pkg/yqlib/doc/Select.md

Select is used to filter arrays and maps by a boolean expression.

Select elements from array

Given a sample.yml file of:

- cat
- goat
- dog

then

yq eval '.[] | select(. == "*at")' sample.yml

will output

cat
goat

Select and update matching values in map

Given a sample.yml file of:

a:
  things: cat
  bob: goat
  horse: dog

then

yq eval '(.a.[] | select(. == "*at")) |= "rabbit"' sample.yml

will output

a:
  things: rabbit
  bob: rabbit
  horse: dog