If a curl request returns a json array, how do I get the number of elements inside that array (.sh/bash script)

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So far my bash script is as follows:

Bash

#!/bin/sh
sessionnumber=0
curl --data '{"command":"listsessions","transaction":"123","adminsecret":"secret"}' -H "Content-Type: application/json" http://127.0.0.1:8088/admin

This successfully returns the following:

{
   "result": "success",
   "transaction": "123",
   "sessions": []
}

I am trying to create a for loop in the .sh script that iterates over each of the elements in the sessions array, and increments the value of sessionnumber by 1 but I am having difficulty parsing the json array that is output from the curl command.

What I have tried:

I have tried a number of things but all of my problems seem to relate to unable to parse the array that is 'sessions' which is inside the returned json array

Posted 6-Jan-22 3:49am

mc96

Updated 6-Jan-22 4:27am

v2

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k5054 · Accepted Answer · 2022-01-06T04:27:00

Parsing JSON using standard tools (grep, awk, sed, etc), is probably more difficult than you imagine. You really need a JSON parser. This is discussed here: bash - Parsing JSON with Unix tools - Stack Overflow[^]
Looking at the home page for jq Parsing JSON with jq[^] it describes itself a "sed for JSON", so it might be a good way to go.

I have not tried this, nor do I know of its suitability for purpose, so Caveat Usor.

If a curl request returns a json array, how do I get the number of elements inside that array (.sh/bash script)

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If a curl request returns a json array, how do I get the number of elements inside that array (.sh/bash script)

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