diff - Using jq or alternative command line tools to compare JSON files

Question

Are there any command line utilities that can be used to find if two JSON files are identical with invariance to within-dictionary-key and within-list-element ordering?

Could this be done with jq or some other equivalent tool?

Examples:

These two JSON files are identical

A:

{
  "People": ["John", "Bryan"],
  "City": "Boston",
  "State": "MA"
}

B:

{
  "People": ["Bryan", "John"],
  "State": "MA",
  "City": "Boston"
}

but these two JSON files are different:

A:

{
  "People": ["John", "Bryan", "Carla"],
  "City": "Boston",
  "State": "MA"
}

C:

{
  "People": ["Bryan", "John"],
  "State": "MA",
  "City": "Boston"
}

That would be:

$ some_diff_command A.json B.json

$ some_diff_command A.json C.json
The files are not structurally identical

Answer 1

If your shell supports process substitution (Bash-style follows, see docs):

diff <(jq --sort-keys . A.json) <(jq --sort-keys . B.json)

Objects key order will be ignored, but array order will still matter. It is possible to work-around that, if desired, by sorting array values in some other way, or making them set-like (e.g. ["foo", "bar"] → {"foo": null, "bar": null}; this will also remove duplicates).

Alternatively, substitute diff for some other comparator, e.g. cmp, colordiff, or vimdiff, depending on your needs. If all you want is a yes or no answer, consider using cmp and passing --compact-output to jq to not format the output for a potential small performance increase.