escaping characters when passing JSON to aws secretsmanager

I have tried to write a script that updates AWS secrets. Yes, the update-secret command already does this, but that will overwrite existing secrets instead of merging them w/ the new content.

For example, suppose my-environment/my-application/secrets has the following content:

{ "db_1_pwd": "secret"}

If I run my script, like this:

>> update_secret my-environment/my-application/secrets '{"db_2_pwd": "secreter"}'

I would expect the new content to be:

{ "db_1_pwd": "secret", "db_2_pwd": "secreter"}

Instead, the new content winds up being this (unescaped) string:

"{\"db_1_pwd\":\"secret\",\"db_2_pwd\":\"secreter\"}"

Here is my script:

#!/bin/shSECRET_ID=$1SECRET_STRING=$2EXISTING_SECRET=`aws secretsmanager get-secret-value --secret-id $SECRET_ID | jq '.SecretString | fromjson'`NEW_SECRET=`echo $EXISTING_SECRET $SECRET_STRING | jq  -s 'add tostring'`echo $NEW_SECRET  # this is printed out for debug purposesaws secretsmanager put-secret-value --secret-id $SECRET_ID --secret-string $NEW_SECRET

Note that it does print out "{\"db_1_pwd\":\"secret\",\"db_2_pwd\":\"secreter\"}" in the echo statement and if I type this on the command line:

>> aws secretsmanager put-secret-value --secret-id my-environment/my-application/secrets --secret-string "{\"db_1_pwd\":\"secret\",\"db_2_pwd\":\"secreter\"}"

it works.

Clearly the script is having issues w/ escaping the quotation marks. Any suggestions on how to fix this?

(It's probably something to do w/ bash as opposed to AWS)