yq/README.md

yaml

yaml is portable command line tool written in go

Allows you to read and update yaml files from bash (or whatever). All in a lovely dependency free binary!

Download latest release

or alternatively install using go get:

go get github.com/mikefarah/yaml

Read examples

yaml r <yaml file> <path>

Basic

Given a sample.yaml file of:

b:
  c: 2

then

yaml r sample.yaml b.c

will output the value of '2'.

Reading from STDIN

Given a sample.yaml file of:

cat sample.yaml | yaml r - b.c

will output the value of '2'.

Splat

Given a sample.yaml file of:

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

then

yaml r sample.yaml bob.*.cats

will output

- bananas
- apples

Handling '.' in the yaml key

Given a sample.yaml file of:

b.x:
  c: 2

then

yaml r sample.yaml \"b.x\".c

will output the value of '2'.

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

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

will output 'sam'

Array Splat

e.g.: given a sample file of

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

then

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

will output:

- fred
- sam

Update examples

Update to stdout

Given a sample.yaml file of:

b:
  c: 2

then

yaml w sample.yaml b.c cat

will output:

b:
  c: cat

Updating yaml in-place

Given a sample.yaml file of:

b:
  c: 2

then

yaml w -i sample.yaml b.c cat

will update the sample.yaml file so that the value of 'c' is cat.

Updating multiple values with a script

Given a sample.yaml file of:

b:
  c: 2
  e:
    - name: Billy Bob

and a script update_instructions.yaml of:

b.c: 3
b.e[0].name: Howdy Partner

then

yaml w -s update_instructions.yaml sample.yaml

will output:

b:
  c: 3
  e:
    - name: Howdy Partner