Put json key/value pairs into a file or json stream from the command line
npm install -g jsonput
$ cat test.json
{"hello": "world"}
$ jsonput test.json hello:mars
$ cat test.json
{"hello":"mars"}
$ cat test.json | jsonput - hello:verden > test.json
$ cat test.json
{"hello" "verden"}
$ jsonput test.json hello:{places:[mars,world]}