How can I pretty-print JSON in a shell script?

Question

With Python 2.6+ you can do:

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

or, if the JSON is in a file, you can do:

python -m json.tool my_json.json

if the JSON is from an internet source such as an API, you can use

curl http://my_url/ | python -m json.tool

For convenience in all of these cases you can make an alias:

alias prettyjson='python -m json.tool'

---

For even more convenience with a bit more typing to get it ready:

prettyjson_s() {
    echo "$1" | python -m json.tool
}

prettyjson_f() {
    python -m json.tool "$1"
}

prettyjson_w() {
    curl "$1" | python -m json.tool
}

for all the above cases. You can put this in .bashrc and it will be available every time in shell. Invoke it like prettyjson_s '{"foo": "lorem", "bar": "ipsum"}'.

Note that as @pnd pointed out in the comments below, in Python 3.5+ the JSON object is no longer sorted by default. To sort, add the --sort-keys flag to the end. I.e. ... | python -m json.tool --sort-keys.

You can use: jq

It's very simple to use and it works great! It can handle very large JSON structures, including streams. You can find their tutorials here.

Usage examples:

$ jq --color-output . file1.json file1.json | less -R

$ command_with_json_output | jq .

$ jq # stdin/"interactive" mode, just enter some JSON

$ jq <<< '{ "foo": "lorem", "bar": "ipsum" }'
{
  "bar": "ipsum",
  "foo": "lorem"
}

Or use jq with identity filter:

$ jq '.foo' <<< '{ "foo": "lorem", "bar": "ipsum" }'
"lorem"

I use the "space" argument of JSON.stringify to pretty-print JSON in JavaScript.

Examples:

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

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

From the Unix command-line with Node.js, specifying JSON on the command line:

$ node -e "console.log(JSON.stringify(JSON.parse(process.argv[1]), null, '\t'));" \
  '{"foo":"lorem","bar":"ipsum"}'

Returns:

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

From the Unix command-line with Node.js, specifying a filename that contains JSON, and using an indent of four spaces:

$ node -e "console.log(JSON.stringify(JSON.parse(require('fs') \
      .readFileSync(process.argv[1])), null, 4));"  filename.json

Using a pipe:

echo '{"foo": "lorem", "bar": "ipsum"}' | node -e \
"\
 s=process.openStdin();\
 d=[];\
 s.on('data',function(c){\
   d.push(c);\
 });\
 s.on('end',function(){\
   console.log(JSON.stringify(JSON.parse(d.join('')),null,2));\
 });\
"

I wrote a tool that has one of the best "smart whitespace" formatters available. It produces more readable and less verbose output than most of the other options here.

underscore-cli

This is what "smart whitespace" looks like:

I may be a bit biased, but it's an awesome tool for printing and manipulating JSON data from the command-line. It's super-friendly to use and has extensive command-line help/documentation. It's a Swiss Army knife that I use for 1001 different small tasks that would be surprisingly annoying to do any other way.

Latest use-case: Chrome, Dev console, Network tab, export all as HAR file, "cat site.har | underscore select '.url' --outfmt text | grep mydomain"; now I have a chronologically ordered list of all URL fetches made during the loading of my company's site.

Pretty printing is easy:

underscore -i data.json print

Same thing:

cat data.json | underscore print

Same thing, more explicit:

cat data.json | underscore print --outfmt pretty

This tool is my current passion project, so if you have any feature requests, there is a good chance I'll address them.