jsontsv

A simple tool to transform JSON into tab-separated line-oriented output amenable to downstream Unix text processing.

Synopsis

input.json:

{
  "title": "Terminator 2: Judgement Day",
  "year": 1991,
  "stars": [
    "Arnold Schwarzenegger",
    "Linda Hamilton"
  ],
  "ratings": {
    "imdb": 8.5
  }
}
{
  "title": "Interstellar",
  "year": 2014,
  "stars": [
    "Matthew McConaughey",
    "Anne Hathaway"
  ],
  "ratings": {
    "imdb": 8.9
  }
}

jsontsv 'title year stars ratings.imdb' < input.json

Outputs this tab-separated text:

Terminator 2: Judgement Day	1991	Arnold Schwarzenegger,Linda Hamilton	8.5
Interstellar	2014	Matthew McConaughey,Anne Hathaway	8.9

Setup

From the project directory,

cabal install

Make sure the installed executable is on your PATH.

Usage

Input should be a stream of JSON objects with mostly uniform keys, separated by whitespace such as newlines. If the objects are wrapped in a JSON array at the top level, use the jq tool by Stephan Dolan to unwrap the objects, e.g.:

curl -s "https://api.github.com/users/danchoi/repos?type=owner&sort=created&direction=desc" \
    | jq '.[]' | jsontsv 'id name stargazers_count open_issues_count' 

outputs

27397673        jsontsv 0       0
26033118        ngrender        24      1
25832026        rdoc    0       0
24756523        treehtml        0       0
24022588        heistexamples   0       0
24022042        hxtexamples     0       0
24005242        jdiff   0       0
23997156        https-types     0       0
22763562        podcasting      0       0
19294791        vimscript       3       0

JSON leaf values are printed as follows:

• Strings and numbers were copied to output.
• Boolean values are output as t or f.
• null is printed as null
• Arrays of leaf values are concatenated into a single comma-separated string

Nested keys

jsontsv 'title duplicates.Rental.HD duplicates.Rental.SD' < input.json

Using a file to designate columns:

jsontsv -f keys  < input.json

Concatenating fields, truncating fields, etc.

This should be done downstream using a tool like AWK.