yq/pkg/yqlib/doc/operators/headers/Main.md

NAME

yq is a portable command-line YAML processor

SYNOPSIS

yq [eval/eval-all] [expression] files..

eval/e - (default) Apply the expression to each document in each yaml file in sequence

eval-all/ea - Loads all yaml documents of all yaml files and runs expression once

DESCRIPTION

a lightweight and portable command-line YAML processor. yq uses jq like syntax but works with yaml files as well as json. It doesn't yet support everything jq does - but it does support the most common operations and functions, and more is being added continuously.

This documentation is also available at https://mikefarah.gitbook.io/yq/

QUICK GUIDE

Read a value:

yq '.a.b[0].c' file.yaml

Pipe from STDIN:

cat file.yaml | yq '.a.b[0].c'

Update a yaml file, inplace

yq -i '.a.b[0].c = "cool"' file.yaml

Update using environment variables

NAME=mike yq -i '.a.b[0].c = strenv(NAME)' file.yaml

Merge multiple files

yq ea '. as $item ireduce ({}; . * $item )' path/to/*.yml

Note the use of ea to evaluate all files at once (instead of in sequence.)

Multiple updates to a yaml file

yq -i '
  .a.b[0].c = "cool" |
  .x.y.z = "foobar" |
  .person.name = strenv(NAME)
' file.yaml

See the documentation for more.

KNOWN ISSUES / MISSING FEATURES

• yq attempts to preserve comment positions and whitespace as much as possible, but it does not handle all scenarios (see https://github.com/go-yaml/yaml/tree/v3 for details)
• Powershell has its own...opinions: https://mikefarah.gitbook.io/yq/usage/tips-and-tricks#quotes-in-windows-powershell

BUGS / ISSUES / FEATURE REQUESTS

Please visit the GitHub page https://github.com/mikefarah/yq/.