I need to get a `key` from JSON in standard bash, and found the following:

```
echo '{"first_key": "value", "second_key": "value2"}' | python -mjson.tool | grep 'first_key'

```

But this returns:

```
"first_key": "value",

```

How can I just return `value`, i.e. not the key, and remove the quotes and comma.

Thanks.