How to pretty-print JSON script?

Question

Is there a (*nix) command-line script to format JSON in human-readable form?

Basically, I want it to transform the following:

{ foo: "lorem", bar: "ipsum" }

... into something like this:

{
    foo: "lorem",
    bar: "ipsum"
}

Thanks!

Answer 1

There is TidyJSON it's C#, so maybe you can get it to compile with Mono, and working on *nix. No guarantees though, sorry.

Answer 2

$ echo '{ "foo": "lorem", "bar": "ipsum" }' \
> | python -c'import fileinput, json;
> print(json.dumps(json.loads("".join(fileinput.input())),
>                  sort_keys=True, indent=4))'
{
    "bar": "ipsum",
    "foo": "lorem"
}

NOTE: It is not the way to do it.

The same in Perl:

$ cat json.txt \
> | perl -0007 -MJSON -nE'say to_json(from_json($_, {allow_nonref=>1}), 
>                                     {pretty=>1})'
{
   "bar" : "ipsum",
   "foo" : "lorem"
}

Answer 3

Thanks to J.F. Sebastian's very helpful pointers, here's a slightly enhanced script I've come up with:

#!/usr/bin/python

"""
Convert JSON data to human-readable form.

Usage:
  prettyJSON.py inputFile [outputFile]
"""

import sys
import simplejson as json


def main(args):
    try:
     inputFile = open(args[1])
     input = json.load(inputFile)
     inputFile.close()
    except IndexError:
     usage()
     return False
    if len(args) < 3:
     print json.dumps(input, sort_keys = False, indent = 4)
    else:
     outputFile = open(args[2], "w")
     json.dump(input, outputFile, sort_keys = False, indent = 4)
     outputFile.close()
    return True


def usage():
    print __doc__


if __name__ == "__main__":
    sys.exit(not main(sys.argv))

Answer 4

J.F. Sebastian's solutions didn't work for me in Ubuntu 8.04, here is a modified Perl version that works with the older 1.X JSON library:

perl -0007 -MJSON -ne 'print objToJson(jsonToObj($_, {allow_nonref=>1}), {pretty=>1}), "\n";'

Answer 5

On *nix, reading from stdin and writing to stdout works better:

#!/usr/bin/env python
"""
Convert JSON data to human-readable form.

(Reads from stdin and writes to stdout)
"""

import sys
import simplejson as json


print json.dumps(json.loads(sys.stdin.read()), indent=4)
sys.exit(0)

Put this in a file (I named mine "prettyJSON" after AnC's answer) in your PATH and chmod +x it, and you're good to go.

Depending on the version of Python you have installed, you may need to replace "import simplejson as json" with "import json".

Answer 6

I use json_xs to format/pretty-print json and yaml data.

Answer 7

for the peeps looking for a quick online thingy: http://www.shell-tools.net/index.php?op=json%5Fformat

Answer 8

Or, with Ruby:

echo '{ "foo": "lorem", "bar": "ipsum" }' | ruby -r json -e 'jj JSON.parse gets'

Answer 9

http://jsonlint.com has a nice validator/formatter if you not looking for a programmatic way of doing it.

Answer 10

With python you can just do

echo '{"foo": "lorem", "bar": "ipsum"}' | python -mjson.tool

Answer 11

The JSON Ruby Gem is bundled with a shell script to prettify JSON:

sudo gem install json
echo '{ "foo": "bar" }' | prettify_json.rb

Answer 12

with perl, use CPAN module JSON::XS.

it installs a command line tool "json_xs"

Validate:

json_xs -t null < myfile.json

Prettify the JSON file src.json to dst.json.

< src.json json_xs > pretty.json

Answer 13

I use JSON.stringify to pretty-print JSON.

Examples:

JSON.stringify({ foo: "lorem", bar: "ipsum" }, null, 4);

JSON.stringify({ foo: "lorem", bar: "ipsum" }, null, '\t');