jq & bash: make JSON array from variable

Tags: arrays json bash jq

I'm using jq to form a JSON in bash from variable values.

Got how to make plain variables

$ VAR="one two three"
$ jq -n "{var:\"$VAR\"}"
  "var": "one two three"

But can't make arrays yet. I have

$ echo $ARR

and want to get something like

  "arr": ["one", "two", "three"]

I only manage to get garbled output like

$ jq -n "{arr: [\"$ARR\"]}"
  "arr": [

How to form JSON array in a correct way? Can jq ever do that?

EDIT: Question was asked when there was only jq 1.3. Now, in jq 1.4, it is possible to do straightly what I asked for, like @JeffMercado and @peak suggested, upvote for them. Won't undo acceptance of @jbr 's answer though.


jq is doing exactly what you tell it to do. jq is not a program for generating JSON, but a tool for querying it. What you are doing with the -n switch is just using it as a pretty printer. So if you want it to print an object with an array containing "one", "two", "three" then you have to generate it.

VAR="one two three"
VAR=$(echo $VAR | sed -e 's/\(\w*\)/,"\1"/g' | cut -d , -f 2-)
echo "{var: [$VAR]}"


As Bryan and others mention below it is indeed possible to generate JSON with jq, and from version 1.4, it's even possible to do what the OP ask directly, see for example Jeff's answer.

By : jbr

Also, u can use syntax: jq --arg keyName "MyVal" '.[]."\($keyName)"[] ./JSONFile.js

for input data like [{"MyVal":"Value1","MyVal":Value2,"NotMyVal":"Value3"}];

to get parsed data from JSON with variables.

This example will print: "Value1" "Value2"

By : alexglue

First you have to use -R to read the raw lines and next you have to slurp all values with -s:

$ echo -e "one\ntwo\nthree" | jq -R . | jq -s '{"arr": .}'
  "arr": [
By : ceving

This video can help you solving your question :)
By: admin