Bash从多行JSON脚本Grep变量？

Question

I have a JSON file that has many instances like this..:

{
  "SensorApp": "Open Hardware Monitor",
  "SensorClass": "Temperature",
  "SensorName": "Intel Core i7-4790: CPU Core #4",
  "SensorValue": "31",
  "SensorUnit": "C",
  "SensorUpdateTime": 0
},
{
  "SensorApp": "Open Hardware Monitor",
  "SensorClass": "Temperature",
  "SensorName": "Intel Core i7-4790: CPU Package",
  "SensorValue": "32",
  "SensorUnit": "C",
  "SensorUpdateTime": 0
},
{
  "SensorApp": "Open Hardware Monitor",
  "SensorClass": "Clock",
  "SensorName": "Intel Core i7-4790: CPU Core #1",
  "SensorValue": "3899.165",
  "SensorUnit": "MHz",
  "SensorUpdateTime": 0
},

And so forth. I need to assign a variable, say var1 to the sensor value in:

{
  "SensorApp": "Open Hardware Monitor",
  "SensorClass": "Temperature",
  "SensorName": "Intel Core i7-4790: CPU Package",
  "SensorValue": "32",
  "SensorUnit": "C",
  "SensorUpdateTime": 0
},

I've tried a few questions already in stackoverflow, however none of them seem to work with multi-lined JSON files.

Any ideas how i can achieve this?

Answer 1

I'm not sure if you want to change the value in the json file to a value of a shell variable or if you want to set a shell variable to the value of the SensorValue field in the json.

However, for both tasks you can use jq :

• Iterating over json values in bash

jq -r '.[].SensorValue' file.json | while read -r value ; do
    # Do something useful with the value
    echo "$value"
done

• Modifying a json file from bash

VALUE=123
jq ".[].SensorValue = $VALUE" file.json

---

Update : In comments you told you want to extract the SensorValue out of that json object where SensorName equals "Intel Core i7-4790: CPU Package" . In jq you are using the select() function for that:

jq -r '.[] | select(.SensorName == "Intel Core i7-4790: CPU Package").SensorValue' file.json

Output:

32