grab IP addresses (but not subnets) from a command (or file) and output them one per line to a new file

{
	"status": "success",
	"result": [{
		"address_details": [{
				"address": "135.138.168.78",
				"serviceType": "go_gateway",
				"addressType": "active",
				"create_time": 1631879023,
				"allow_listed": false
			},
			{
				"address": "135.138.168.79",
				"serviceType": "gp_gateway",
				"addressType": "active",
				"create_time": 1631879023,
				"allow_listed": false
			}
		],
		"zone": "Germany",
		"addresses": [
			"135.138.168.78",
			"135.138.168.79"
		],
		"zone_subnet": [
			"137.183.192.0/18",
			"208.27.0.0/16",
			"34.3.0.0/16",
			"34.199.0.0/16",
			"66.59.192.0/19",
			"165.11.128.0/17",
			"135.138.0.0/16",
			"130.141.0.0/16",
			"165.185.0.0/16"
		],
		"addresses_v6": [],
		"address_details_v6": []
	}]
}

Here is some sanitized fake example output of a command I'm using an API to pull.

I only need the actual IP addresses, not the subnets, and I only need the IP addresses once.

From the above example the hopeful output of this would just be the two IP addresses on two lines, like this

135.138.168.78
135.139.168.79

This is just one block of output from about 10 that are in the output/file, all formatted just like this.

Using my mediocre skillset and regex, I attempted to pull this information using grep and awk and had no real success, getting either multiples of the IP addresses in my output, or both the IPs and the subnets.

EDIT - updated with the validated JSON.

• now getting an error using the command
  jq --raw-output '.addresses[]'

"jq: error (at <stdin>:37): Cannot iterate over null (null)
exit status 5"

tried adding a "?" after the square brackets and it outputs nothing.

tried doing '.result.addresses[]' or '.status.addresses[]'

get "jq: error (at <stdin>:37): Cannot index string with string "addresses"
exit status 5"

Assuming the input is valid JSON (your provided sample needs the following fixes to turn it into one (see the specs at https://www.json.org/):

• a document cannot just start with a field name, here "address_details":, you have to open an object with curly braces { - just like as you do close it at the end.

• Strings have to be wrapped into double qoutes ("). For "zone": “Germany” you can see that “Germany” uses different ones.

), then the following stedolan/jq filter can extract what you want:

• .addresses traverses to the array under the "addresses" field name.
• .[] iterates through the items of that array (when contracting with a field name, the initial dot is omitted)
• the --raw-output flag turns the outputs into raw text (until then they are JSON strings, i.e. wrapped into quotes as discussed above)

jq --raw-output '.addresses[]' file.json

135.138.168.78
135.138.168.79

If in your calling environment you are using a pipeline (a program produces the JSON output, and you want to process it on the fly without first saving it into a file), jq can also read in from stdin:

… | jq --raw-output '.addresses[]'

To easily play around with jq, there is https://jqplay.org/. Enter the jq filter (.addresses[] in this case) into the upper left box, and the input JSON into the lower left box, and the (still JSON-encoded) result is immediately shown on the right side. Tick the checkbox reading Raw Output to apply the --raw-output flag we used earlier. Below the input boxes you are shown a command ready to be used on the command line, compiled from the inputs you have made above. Following this example it should now read jq --raw-output '.addresses[]'. Here's a link that brings you right into this final state: https://jqplay.org/s/BMmPjsL6sUT (valid until the site maintainers decide to reset the site which happens every now and then.)

To dive more into the jq language, have a look at the (clickable) examples on the bottom of the jqplay.org site, and consult the manual at https://stedolan.github.io/jq/manual/.

cat <file> | grep -Eo '"[0-9]{1,3}\.[0-9]{1,3}\.[0-9]{1,3}\.[0-9]{1,3}"' | tr -d '"' | sort -u

should do it

so, again, totally new to this. Trial and error got me to this command.

jq --raw-output '.result | .[].addresses[]'

It works. I have no idea if this is a well-formatted or thought out jq command, but it outputs the IPs in both my test file and the real data.