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Read

yq r <yaml_file|json_file> <path>

This command can take a json file as input too, and will output yaml unless specified to export as json (-j)

Basic

Given a sample.yaml file of:

b:
  c: 2

then

yq r sample.yaml b.c

will output the value of '2'.

From Stdin

Given a sample.yaml file of:

cat sample.yaml | yq r - b.c

will output the value of '2'.

Splat

Given a sample.yaml file of:

---
bob:
  item1:
    cats: bananas
  item2:
    cats: apples

then

yq r sample.yaml bob.*.cats

will output

- bananas
- apples

Multiple Documents - specify a single document

Given a sample.yaml file of:

something: else
---
b:
  c: 2

then

yq r -d1 sample.yaml b.c

will output the value of '2'.

Multiple Documents - read all documents

Reading all documents will return the result as an array. This can be converted to json using the '-j' flag if desired.

Given a sample.yaml file of:

name: Fred
age: 22
---
name: Stella
age: 23
---
name: Android
age: 232

then

yq r -d'*' sample.yaml name

will output:

- Fred
- Stella
- Android

Arrays

You can give an index to access a specific element: e.g.: given a sample file of

b:
  e:
    - name: fred
      value: 3
    - name: sam
      value: 4

then

yq r sample.yaml 'b.e[1].name'

will output 'sam'

Note that the path is in quotes to avoid the square brackets being interpreted by your shell.

Array Splat

e.g.: given a sample file of

b:
  e:
    - name: fred
      value: 3
    - name: sam
      value: 4

then

yq r sample.yaml 'b.e[*].name'

will output:

- fred
- sam

Note that the path is in quotes to avoid the square brackets being interpreted by your shell.

Keys with dots

When specifying a key that has a dot use key lookup indicator.

b:
  foo.bar: 7

yaml r sample.yaml 'b[foo.bar]'

yaml w sample.yaml 'b[foo.bar]' 9

Any valid yaml key can be specified as part of a key lookup.

Note that the path is in quotes to avoid the square brackets being interpreted by your shell.

Keys (and values) with leading dashes

If a key or value has leading dashes, yq won't know that you are passing a value as opposed to a flag (and you will get a 'bad flag syntax' error).

To fix that, you will need to tell it to stop processing flags by adding '--' after the last flag like so:

yq n -t -- --key --value

Will result in

` --key: --value