I have tried to get hands on some JSON file validators. I came across jq. But after running 'jq . file.json' I got JSON formatted output. That command didn't gave me validation of JSON in my file.
I want to know how I can check the syntax or validate JSON format in my file in Ubuntu. Please advise me.


Try jsonlint:

sudo apt install jsonlint

The basic usage syntax is


You find its manual by typing man jsonlint or visiting its online manpage:

An excerpt:

       jsonlint - A JSON syntax validator and formatter tool

       jsonlint [-v][-s|-S][-f|-F][-ecodec]inputfile.json...


       The  return  status  will  be  0 if the file is legal JSON, or non-zero
       otherwise.  Use -v to see the warning details.


       -v, --verbose
              Show details of lint checking
       -s, --strict
              Be strict in what is considered legal JSON (the default)
       -S, --nonstrict
              Be loose in what is considered legal JSON
       -f, --format
              Reformat the JSON (if legal) to stdout


So you can see whether your JSON is valid by checking the return code of jsonlint. You can see it by running echo $? right afterwards (0=OK, 1=invalid), or by evaluating it using &&, || or if.

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  • What exactly jsonlint will do, please advise – Jaffer Wilson Jan 27 '17 at 10:11
  • 8
    When I installed the jsonlint package on Ubuntu just now, the installed binary was for some reason called jsonlint-php rather than jsonlint. It appears to work correctly, but I had to remember the dpkg-query -L command to figure out what it had actually installed. – Daniel McLaury Nov 28 '18 at 17:39

jq will spit out the error explicitly, and you can also check the exit status, which is 1 for parse errors, and obviously 0 for successes.

For example:

% jq '.' <<<'{"foo": "spam", "bar": 1}'
  "bar": 1,
  "foo": "spam"

% echo $?

Now, let's replace : with = after "bar"-- making the input an invalid json:

% jq '.' <<<'{"foo": "spam", "bar"= 1}'
parse error: Invalid numeric literal at line 1, column 23

% echo $?                                  
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  • But jq doesn't detect this incomplete document jq '.' <<<'{"foo' – Joe Aug 6 '18 at 19:21
  • @Joe It's not showing anything on output expectedly. Did you mean, it should raise an error or something instead? – heemayl Aug 7 '18 at 12:37
  • Yes. jsonlint (the javascript version available at jsonlint.com), for example, reports an error for that incomplete document. – Joe Aug 7 '18 at 23:06
  • jq sucks, a valid json file will report "jq: error: syntax error, unexpected '/', expecting $end (Unix shell quoting issues?) at <top-level>, line 1:" – Liu Hao Jan 18 at 3:59

You can do this using python json.tool module

echo '{"name": "dedunu", "country": "LKA"}' | python -m json.tool

If you have a file you can use it as below.

python -m json.tool file.json

But the problem with this command is that you won't get a detail about the problem in JSON file. I found the answer from this link.

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I tried jsonlint but it's doesn't work.

jq . may-file.json work nice!

Hope this feedback is helpful.

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