I've spent a lot of time in the past modifying JSON/yaml for helm charts and not only and I always wanted to have a tool that would do it for me.

sackmesser is different from other tools like jq in a way that it's targeted exclusively to modify documents and also can consume as well as output both yaml/JSON. It's quite simple to add new formats if necessary as well as to add support for other operations.

A nice part of the project is that a JSON object is a valid argument for operations like push, set, or merge, which makes it super easy to modify multiple parts of the project. If that's not enough, you can always supply multiple operations.

I haven't focused on speed and overall polishness, this part still needs some attention.

Hope you like it!