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Accepted
alexus
Asked: 2023-06-30 03:06:52 +0800 CST

jq: error: X/0 is not defined at <top-level>, line 1:

  • 772

I'm trying to extract value from the bellow JSON:

% export test='{"a-b-c":"x-y-z"}'
% echo $test
{"a-b-c":"x-y-z"}
% echo $test | jq .a-b-c
jq: error: b/0 is not defined at <top-level>, line 1:
.a-b-c
jq: error: c/0 is not defined at <top-level>, line 1:
.a-b-c
jq: 2 compile errors
% echo $test | jq '."a-b-c"'
"x-y-z"
%

while the last line "works", my end goal is to have shell script and substitute "a-b-c" parameter with variable, however due to I must use single quotes, the actual value isn't being passed..

% export var1=a-b-c
% echo $var1
a-b-c
% echo $test | jq '."$var1"'
null
%

Please advise)

bash

2 Answers

  1. Best Answer

    Use the --arg option to initialize a jq variable with a shell variable's value.

    jq --arg key "$var1" '.[$key]'

    See Invoking jq and scroll down to --arg

    • 2

  2. I've got it to work:

    % echo $test | jq ".\"$var1\""
"x-y-z"
%

    Thanks!

    • 0