With

Use the with operator to conveniently make multiple updates to a deeply nested path, or to update array elements relatively to each other. The first argument expression sets the root context, and the second expression runs against that root context.

Update and style

Given a sample.yml file of:

a:
  deeply:
    nested: value

then

yq 'with(.a.deeply.nested; . = "newValue" | . style="single")' sample.yml

will output

a:
  deeply:
    nested: 'newValue'

Update multiple deeply nested properties

Given a sample.yml file of:

a:
  deeply:
    nested: value
    other: thing

then

yq 'with(.a.deeply; .nested = "newValue" | .other= "newThing")' sample.yml

will output

a:
  deeply:
    nested: newValue
    other: newThing

Update array elements relatively

The second expression runs with each element of the array as it's contextual root. This allows you to make updates relative to the element.

Given a sample.yml file of:

myArray:
  - a: apple
  - a: banana

then

yq 'with(.myArray[]; .b = .a + " yum")' sample.yml

will output

myArray:
  - a: apple
    b: apple yum
  - a: banana
    b: banana yum