How to extract value from json contained in a variable using jq in bash

Question

I am writing a bash script which has a json value stored in a variable now i want to extract the values in that json using Jq. The code used is.

json_val={"code":"lyz1To6ZTWClDHSiaeXyxg","redirect_to":"http://example.com/client-redirect-uri?code=lyz1To6ZTWClDHSiaeXyxg"}
  code_val= echo"$json_val" | jq '.code'

This throws an error of no such file or direcotry.

If i change this to

json_val={"code":"lyz1To6ZTWClDHSiaeXyxg","redirect_to":"http://example.com/client-redirect-uri?code=lyz1To6ZTWClDHSiaeXyxg"}
  code_val=echo" $json_val " | jq '.code'

This does not throws any error but the value in code_val is null.

If try to do it manually echo {"code":"lyz1To6ZTWClDHSiaeXyxg","redirect_to":"http://example.com/client-redirect-uri?code=lyz1To6ZTWClDHSiaeXyxg"} | jq '.code' it throws parse numeric letter error.

how can i do it in first case.

anubhava · Accepted Answer · 2020-01-01 10:32:53Z

15

You may use this:

json_val='{"code":"lyz1To6ZTWClDHSiaeXyxg","redirect_to":"http://example.com/client-redirect-uri?code=lyz1To6ZTWClDHSiaeXyxg"}'
code_val=$(jq -r '.code' <<< "$json_val")
echo "$code_val"

lyz1To6ZTWClDHSiaeXyxg

Note following changes:

Wrap complete json string in single quotes
use of $(...) for command substitution
Use of <<< (here-string) to avoid a sub-shell creation

PS: If you're getting json text from a curl command and want to store multiple fields in shell variables then use:

read -r code_val redirect_to < <(curl ... | jq -r '.code + "\t" + .redirect_to')

Where ... is your curl command.

edited Jan 1, 2020 at 10:32

answered Jan 1, 2020 at 10:21

anubhava

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4 Comments

Rahul Over a year ago

in this you have put the json response in ''(single quotes) which makes changes it to literal string. I cannot do this coz i am getting the json_val as a curl response after i run the curl command in earlier line and i save the response in that variable. Or please suggest a way to convert the data in variable to string and then pass to jq.

Rahul Over a year ago

yeah but there are multiple fields which i need to extract and save in two different variable from the same curl response. Can you suggest a way to extract two values and save in two diff variable from the curl json response. That would do my work.

Rahul Over a year ago

it does work but also throws errors of echoset not defined read -r code_val redirect_to < <(curl 5dba6fe9eddc81001495f72c.mockapi.io/tyk_test/rate_ poc | jq -r '.rate + "\t" + .individual') echo"$code_val" echo"$redirect_to"

anubhava Over a year ago

Run curl with my suggested ka command on shell and see if that runs fine

bloodyKnuckles · Accepted Answer · 2022-05-11 15:36:46Z

1

If try to do it manually:

$ echo {"code":"lyz1To6ZTWClDHSiaeXyxg","redirect_to":"http://example.com/client-redirect-uri?code=lyz1To6ZTWClDHSiaeXyxg"} | jq '.code'

...it throws parse numeric letter error.

seems like you did not escape the string of the echo command. in your case, escaping with a singe-quote (apostrophe ') will do - same as you did with the jq json-path argument ('.code')

$ echo '{"code":"lyz1To6ZTWClDHSiaeXyxg","redirect_to":"http://example.com/client-redirect-uri?code=lyz1To6ZTWClDHSiaeXyxg"}' | jq '.code'
"lyz1To6ZTWClDHSiaeXyxg"

edited May 11, 2022 at 15:36

bloodyKnuckles

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answered Jan 1, 2020 at 16:36

Mr.

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