How can I copy a JSON block to another file?-CodePudding

I have two JSON files with the following content:

foo.json:

{
  "name": "foo",
  "block": {
    "one": 1,
    "two": "2"
  },
  "otherData": {
    "two": 1,
    "one": "2"
  }
}

bar.json:

{
  "name": "bar"
}

I want to copy the block from foo.json to bar.json in one line so bar.json looks like this:

{
  "name": "bar",
  "block": {
    "one": 1,
    "two": "2"
  }
}

I tried:

jq --argjson block '{"block": "$(jq '.block' ./foo.json)"}' '.  = [$block]' ./bar.json | sponge ./bar.json

CodePudding user response：

The operator can be used to combine multiple objects together. Having the object enclosed with {} selects the whole object for inclusion.

jq ' .   ( input | {block} )' bar.json foo.json | sponge bar.json

Note: sponge is a utility from the moreutils package, which needs to be installed separately on your system. See setup instructions on the moreutils page

Exercise caution while using the tool, because it overwrites whatever content that is coming in from the standard input to the target file specified. If not completely sure, verify the result by writing to standard output before running sponge.