How to count items in JSON object using command line?

Question

Just throwing another solution in the mix...

Try jq, a lightweight and flexible command-line JSON processor:

jq length /tmp/test.json

Prints the length of the array of objects.

The shortest expression is

curl 'http://…' | jq length

You can also use jq to track down the array within the returned json and then pipe that in to a second jq call to get its length. Suppose it was in a property called records, like {"records":[...]}.

$ curl https://my-source-of-json.com/list | jq -r '.records | length'
2
$ 

A simple solution is to install jshon library :

jshon -l < /tmp/test.json
2

If the JSON is being read from a file, try this -

number_of_objects=`jq '. | length' json_file_name.json`
echo $number_of_objects

If the JSON array is inside a key in the JSON as shown below -

{
  "fruits": [
    "apples",
    "oranges",
    "pears"
  ]
}

try this -

number_of_objects=`jq '.fruits | length' json_file_name.json`
echo $number_of_objects

(You'll have to download jq for this solution to work)