Unfortunately, it doesn't merge/concatenate arrays. Sometimes that's what you want (you want the 2nd value to override the 1st but sometimes not.

If you want it to concatenate instead, here are some workarounds:

1. https://stackoverflow.com/questions/53661930/jq-recursively-merge-objects-and-concatenate-arrays

2. If you only need/want to concatenate for some fixed list of keys, you could do it more simply like this (but could get repetitive to repeat for each key you want it for):

⟫ jq -n '[{hosts: ["a"]}, {hosts: ["b"]}] | .[]' | jq -s '.[0] * .[1] * {hosts: (.[0].hosts + .[1].hosts)}' { "hosts": [ "a", "b" ] }

Good defaults are sometimes hard to recognize, especially when the tool is complex.

Questioning the defaults-- and deciding why you would keep them or change them-- is a good antidote to dismissing something due to not understanding it.

If you can't understand why you don't like the defaults, then decide what you would choose instead and why you would change the default as it stands. Does the default make it easy to do the "right" thing AND hard to do the "wrong" thing? The second part of that statement is the most important since it might not be obvious what the "right" thing is.

Even if you don't like the defaults, ask yourself if they continually lead you away from perils and problems that would plague you if a different set of defaults were chosen?