Passed command line argument in double quotes to c

Question

My script is taking the command line argument and it needs to pass this to curl command in double quotes. This is the simplified version of what I tried so far:

json=$1;
echo $json;

curl -X POST -d '{"asin":\"$json\", "template":"bolt","version":"1d"}' -H "Content-Type: application/json" http://someURL

But its not working. Please help

Answer 1

$-variables in single quoted strings don't get expanded. The -d argument needs be in double quotes, or at least the $json part needs to be:

curl -X POST -d '{"asin":"'"$json"'", "template":"bolt","version":"1d"}' -H "Content-Type: application/json" http://someURL

'-terminates the single-quoted string, then "$json" follows, and then ' starts an adjacent single quoted string.

The "$json" variable shouldn't expand to a string containing unescaped double quotes or the resulting json will be broken.