Convert json to yaml in linux bash

Is it possible with bash?

The short and reasonable answer is: no! Bash won’t do it in a reliable way for you.

Basic Linux Tools that convert JSON to YAML

The goal here should be to use standard tools that in the best case you do not need to install. The basic scripting languages and their standard modules are good candidates. Also yq (the YAML pendant to jq) becoming more popular might be soon available in Linux distros.

Ruby

ruby -ryaml -rjson -e 'puts YAML.dump(JSON.parse(STDIN.read))' <input.json

Python

python -c 'import sys, yaml, json; print(yaml.dump(json.loads(sys.stdin.read())))' <input.json

Perl

perl -MYAML -MJSON -0777 -wnl -e 'print YAML::Dump(decode_json($_))' input.json

yq

yq -oy input.json

jq

A nice jq based solution working for a JSON subset (non-multiline strings) has been posted by Jeff Mercado here:

Place the following into ~/.jq

def yamlify2:
    (objects | to_entries | (map(.key | length) | max + 2) as $w |
        .[] | (.value | type) as $type |
        if $type == "array" then
            "\(.key):", (.value | yamlify2)
        elif $type == "object" then
            "\(.key):", "    \(.value | yamlify2)"
        else
            "\(.key):\(" " * (.key | $w - length))\(.value)"
        end
    )
    // (arrays | select(length > 0)[] | [yamlify2] |
        "  - \(.[0])", "    \(.[1:][])"
    )
    // .
    ;

And convert using

jq -r yamlify2 input.json