How to extract a value from json response using shell script

Question

{"expand":"renderedFields,names,schema,operations,editmeta,changelog,versionedRepresentations","id":"15114","self":"https://brg-jira-tst.state.mi.us/rest/api/2/issue/15114","key":"BRGTEST-11","fields":{"issuetype":{"self":"https://brg-jira-tst.state.mi.us/rest/api/2/issuetype/10200","id":"10200","description":"A task that needs to be done associated with Bridges project","iconUrl":"https://brg-jira-tst.state.mi.us/secure/viewavatar?size=xsmall&avatarId=10318&avatarType=issuetype","name":"Task","subtask":false,"avatarId":10318},"customfield_11500":"QAT"}}

Above is my json response which is stored in a.json

I want to extract the value of customfield_11500 from this a.json response using shell script. How to do it

In this case the Output for my shell command must give the result as "QAT"

---

Formatted JSON for the scrolling-averse:

{
  "expand": "renderedFields,names,schema,operations,editmeta,changelog,versionedRepresentations",
  "id": "15114",
  "self": "https://brg-jira-tst.state.mi.us/rest/api/2/issue/15114",
  "key": "BRGTEST-11",
  "fields": {
    "issuetype": {
      "self": "https://brg-jira-tst.state.mi.us/rest/api/2/issuetype/10200",
      "id": "10200",
      "description": "A task that needs to be done associated with Bridges project",
      "iconUrl": "https://brg-jira-tst.state.mi.us/secure/viewavatar?size=xsmall&avatarId=10318&avatarType=issuetype",
      "name": "Task",
      "subtask": false,
      "avatarId": 10318
    },
    "customfield_11500": "QAT"
  }
}

Solution 1

With recent versions of the ksh93 shell (v- or above):

read -m json j < file.json &&
  print -r -- "${j.fields.customfield_11500}"

Or use the widely available (though generally not installed by default) jq json processor tool:

jq -r '.fields.customfield_11500' file.json

Solution 2

Based in this post and using the formatted json file

grep -oP '(?<="customfield_11500": ")[^"]*' a.json

Comments

[Angel Todorov]

JSON is complex enough to require the use of a JSON-specific parser. I would use jq or, if you can't install that, python or perl.

[Kusalananda]

Why the cat there?

[Dmitry L.]

not required (just my way of building examples), one could do it like: jtc -w'<customfield_11500>l' a.json

[Chai]

I don’t want to to use customfield_11500 directly.I will pass it to variable a and then I want to grep the value using $a.Kindlt let me know how to grep the value from variable

[Sam]

@Chai Well you could put this in a bash script and create a method called key or something that does this, and replace '(?<="customfield_11500": ")[^"]*' with '(?<="'$1'": ")[^"]*' and then call key your_key I think, as long as you source your bash script, this might not work exactly