Add a simple key-value pair to existing JSON using jq - jq

I am totally new to jq so sorry for the simple question, but I can't seem to find an answer to this. How do I simply concatenate a new JSON key/value pair to some existing JSON. For example, say I have:
{"key1": "value1"}
in variable A in a bash script. I now want to add:
{"key2": "value2"}
to A using jq so that that the resulting contents of A are:
{"key1": "value1",
"key2": "value2"}
How do I do this?

At a bash prompt:
A='{"key1": "value1"}'
$ echo $A
{"key1": "value1"}
A=$(jq -n --argjson A "$A" '$A + {"key2": "value2"}')
$ echo $A
{ "key1": "value1", "key2": "value2" }
$

Related

jq returns "Invalid numeric literal" with --arg

The command below is returning an error (jq version: 1.6):
$ jq --arg b bar . <<< '{ "foo": $b }'
parse error: Invalid numeric literal at line 1, column 12
Expected output:
{
"foo": "bar"
}
The jq 1.6 manual describes the --arg option thusly:
--arg name value: This option passes a
value to the jq program as a predefined variable. If you run jq with
--arg foo bar, then $foo is available in
the program and has the value "bar". Note that
value will be treated as a string, so --arg foo
123 will bind $foo to "123".
Named arguments are also available to the jq program as
$ARGS.named.
My usage appears correct. What's going on here?
My variable call was not within the jq program
The here-string I'm passing into jq
{ "foo": $b }
is not "the jq program" mentioned in the manual's --arg description. The lone . was the entire program, and did not use the variable $b.
I was trying to construct JSON from scratch by passing in my pattern on stdin. Instead, I should have provided the --null-input option, and replaced the . with the pattern I was attempting to pass in.
Description of --null-input
--null-input/-n:
Don't read any input at all! Instead, the filter is run once
using null as the input. This is useful when using jq as
a simple calculator or to construct JSON data from scratch.
Here's the correct invocation:
$ jq --arg b bar --null-input '{ "foo": $b }'
{
"foo": "bar"
}

jq syntax help for querying lists output

I need help in correcting jq test cases syntax. Following is output file & trying to test ID list with command below. Gives error index to string type.
[[ $(echo $output| jq -r '.output.value[] | select(.identity).id_list') == *"id2"* ]]
output = {
"resource_output": {
"value": {
"identity": [
{
"id_list": [
"/subscriptions/---/id1",
"/subscriptions/---/id2",
"/subscriptions/--/id3"
],
"principal_id": "",
"tenant_id": "",
"type": "managed"
}
]
}
}
Your query does not match the sample JSON, and you have not indicated what output you are expecting, but the following variation of your query illustrates how to use select and test with your data along the lines suggested by your attempt:
echo "$output" |
jq -r '.resource_output.identity[].id_list[] | select(test("id2"))'
Output:
/subscriptions/---/id2

jq: pass string argument without quotes

I would like to pass an argument without quotes (JQ arg has double quotes by default) since it should be used as a filter. For e.g.
propt='.properties'
final=($(jq -r -c --arg p $propt '$p' sample.json))
echo $final
sample.json
{
"type": "object",
"description": "Contains information",
"properties": {
"type": {
"description": "Type"
}
}
}
So ultimately it prints out .properties instead of the expected {"type":{"description":"Type"}}
I use a bash shell for this purpose.
Please let me know what I am doing wrong.
If I understand you correctly, you're getting sidetracked by thinking you need to set up a variable in jq, instead of just letting the shell do an expansion:
% foo='.properties'
% jq -r -c "$foo" sample.json
output:
{"type":{"description":"Type"}}
Note the double quotes on $foo to still allow the shell to expand the variable to .properties. That said you could unsafely use: jq -r -c $foo sample.json
You can't use --arg in that way. The value of a --arg is a string, not a jq filter expression. If you do --arg p .properties, then $p will contain the string ".properties", it won't be evaluated as a program. Find a different way to do what you want, perhaps by defining a function.
For example, if you prefixed your program with def p: .properties; then you could use .|p in your program in the way that you're using $p now, and it would access the .properties of whatever value is in context.
Since jq does not have an “eval” function, the appropriate way to specify a path programmatically in jq is using a JSON array in conjunction with jq’s getpath and setpath built-ins, as appropriate.
Thus in your case you could use the -—argjson command-line option to pass in the path of interest, e.g.
-—argson p '["properties"]'
and your jq program would use getpath($p).
Needless to say, this approach works for arbitrarily nested paths.

Extract fields from json using jq

I am trying write a shell script that will get some json from URL and parse the json and extract fields.
This is what is done so far.
#!/bin/bash
token=$(http POST :3000/signin/frontm user:='{"email": "sourav#frontm.com", "password": "Hello_789"}' | jq -r '.data.id_token')
cred=$(http POST :3000/auth provider_name:frontm token:$token user:=#/tmp/user.json | jq '{ creds: .creds, userUuid: .user.userId }')
echo $cred
access=$(jq -r "'$cred'")
echo $access
So the output from echo $cred is a json:
Eg:
{ "creds": { "accessKeyId": "ASIAJPM3RDAZXEORAQ5Q", "secretAccessK
ey": "krg5GbU6gtQV+a5pz4ChL+ECVJm+wKogjglXOqr6", "sessionToken": "Ag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" }, "userUuid": "mugqRKHmTPxk
obBAtwTmKk" }
So basically I am stuck here .. how do i parse this json in $cred further and basically want to get access to say accessKeyId using jq further?
I wonder if the variable $cred really holds a string formated in 67 columns, but if that so, tr might help to remove the newline and extract the accessKeyId using jq:
echo "$cred" | tr -d '\n' | jq -r '.creds.accessKeyId'

How to do parse json array dynamically in shell script using jq too in shell script

Suppose I have the following json in a file json.txt
{
"first_name": "John",
"last_name": "Smith",
"things_carried": [
"apples",
"hat",
"harmonica"
],
"children": [
{
"first_name": "Bobby Sue",
"last_name": "Smith"
},
{
"first_name": "John Jr",
"last_name": "Smith"
}
]
}
In shell script I had written the logic to find the size of children array using jq tool .
size=cat json.txt | jq '.children | length'
i=0
while [ $i -le $size ]
do
array[$i]=$(cat json.txt | jq '.children[$i]')
i=`expr $i + 1`
done
On running this it gives the following error -
.children[$i] 1 compile error
It seems that it is not able to replace the variable i in the children[] array , as because if we give the expression -
array[$i]=$(cat json.txt | jq '.children[0]')
it runs well .
Can someone help me .
You're using single quotes around the jq program. Shells do not interpolate variables inside single quotes; this is intentional and the jq manual recommends using single quotes around programs for this reason.
An argument syntax is provided by jq for this purpose. This syntax allows you to set jq variables to the value of shell variables. You could replace your current jq invocation with this:
array[$i]=$(cat json.txt | jq --arg i $i '.children[$i | tonumber]')
It looks like you're just trying to set the children to a bash array variable.
You don't need to loop, just set the array directly.
$ IFS=$'\n'; array=($(jq -c '.children[]' json.txt))
You should use the following syntax:
array[$i]=$(cat json.txt | jq '.children['${i}']')

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