Linux CLI - How to get substring from JSON jq + grep?

Question

I need to pull a substring from JSON. In the JSON doc below, I need the end of the value of jq '.[].networkProfile.networkInterfaces[].id' In other words, I need just A10NICvw4konls2vfbw-data to pass to another command. I can't seem to figure out how to pull a substring using grep. I've seem regex examples out there but haven't been successful with them.

[
  {
    "id": "/subscriptions/blah/resourceGroups/IPv6v2/providers/Microsoft.Compute/virtualMachines/A10VNAvw4konls2vfbw",
    "instanceView": null,
    "licenseType": null,
    "location": "centralus",
    "name": "A10VNAvw4konls2vfbw",
    "networkProfile": {
      "networkInterfaces": [
        {
          "id": "/subscriptions/blah/resourceGroups/IPv6v2/providers/Microsoft.Network/networkInterfaces/A10NICvw4konls2vfbw-data",
          "resourceGroup": "IPv6v2"
        }
      ]
    }
  }
]

score 7 · Accepted Answer · answered Apr 24 '17 at 18:30

7

In your case, sub(".*/";"") will do the trick as * is greedy:

.[].networkProfile.networkInterfaces[].id | sub(".*/";"")

answered Apr 24 '17 at 18:30

peak

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Mark Reed · Answer 2 · 2017-04-25T13:54:10.527

7

Try this:

jq -r '.[]|.networkProfile.networkInterfaces[].id | split("/") | last'

The -r tells JQ to print the output in "raw" form - in this case, that means no double-quotes around the string value.

As for the jq expression, after you access the id you want, piping it (still inside jq) through split("/") turns it into an array of the parts between slashes. Piping that through the last function (thanks, @Thor) returns just the last element of the array.

edited Apr 25 '17 at 13:54

answered Apr 24 '17 at 18:34

Mark Reed

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1

Or `.[] | .networkProfile.networkInterfaces[].id | split("/") | last` – Thor Apr 25 '17 at 10:04

score 2 · Answer 3 · answered Apr 25 '17 at 10:06

2

If you want to do it with grep here is one way:

jq -r '.[].networkProfile.networkInterfaces[].id' | grep -o '[^/]*$'

Output:

A10NICvw4konls2vfbw-data

answered Apr 25 '17 at 10:06

Thor

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Linux CLI - How to get substring from JSON jq + grep?

3 Answers3