A group of utility applications to make working with the JSON file format easier, especially for shell scripting.

• jsonread - reads a field from a specified JSON file.
• jsonwrite - writes a field (and optional sub-fields) and its value to a specified JSON file.
• jsonsemver - implementation of semantic versioning (semver.org) using JSON to store the version data. Includes functionality to auto-increment version numbers, making automating version numbers with scripts easy.
• jsonpp - pretty-prints a JSON file.

json-utils requires the json-c library, which can be found on GitHub: https://github.com/json-c/json-c

To compile json-utils, simply run make:

$ make all

The compiled files will be located in ./build/.

jsonread can read fields in the given JSON file, even if they are nested in an array or object. Given the following JSON file:

{
  "obj": {
    "sub1": {
      "one": 1,
      "two": 2
    }
}

jsonread can read any of these fields:

• $ jsonread myfile.json obj sub1 returns { "one": 1, "two": 2 }
• $ jsonread myfile.json obj sub1 one returns 1
• $ jsonread myfile.json obj sub1 two returns 2

jsonread can also access array items:

Given the following JSON file:

{
  "my_array":[
    [2,3,4],
    {
      "five":5,
      "six":6
    },
    7
  ],
}

• $ jsonread myfile.json my_array returns [ [ 2, 3, 4 ], { "five": 5, "six": 6 }, 7 ]
• $ jsonread myfile.json my_array 0 returns [ 2, 3, 4 ]
• $ jsonread myfile.json my_array 0 1 returns 3
• $ jsonread myfile.json my_array 1 five returns 5

jsonwrite is a utility for writing data to a new or existing JSON file. The syntax is jsonwrite file.json field [sub-field, ...] new_value

• $ jsonwrite test.json hello world "hello world!" writes the following JSON to test.json:

{
  "hello":{
    "world":"hello world!"
  }
}

You may specify an unlimited number of sub fields, such as:

• $ jsonwrite test.json one two three four five 5

You may also just specify one field:

• $ jsonwrite test.json hello "world" which writes the following to test.json:

{
  "hello":"world"
}

jsonsemver is a utility for working with semantic version data. It includes auto-incrementing any of the version numbers, incrementing patch by default until it reaches 100, at which point minor is incremented, and patch is reset to 0. It is especially useful if you need to manage a project/application version using scripts.

Given the following JSON file, app-version.json:

{
  "major":7,
  "minor":1,
  "patch":5,
  "prerelease":"beta"
}

$ jsonsemver app-version.json $ jsonsemver app-version.json -s outputs "7.1.6-beta", since the first time it was executed, it incremented the patch field. Calling jsonsemver with the -s parameter outputs the version string ONLY, and does not auto-increment the version number.

jsonpp is a simple utility that pretty-prints the contents of a JSON file.

Given the following test.json file:

{"hello":{"world":"hello world!"}}

• $ jsonpp test.json outputs the following:

{
  "hello":{
    "world":"hello world!"
  }
}

• jsonwrite: crash when overwriting an existing field with sub-fields

• add full support to jsonsemver for command line flag processing
• ?

The json-utils project is open source and is available under the MIT license.