Replace a keyword with the content of the file - json

Question

I have a templatized json file called template.json as below:
{
"subject": "Some subject line",
"content": $CONTENT,
}
I have another file called sample.json with the json content as below:
{
"status": "ACTIVE",
"id": 217,
"type": "TEXT",
"name": "string",
"subject": "string",
"url": "contenttemplates/217",
"content": {
"text": "hello ${user_name}",
"variables": [{
"key": "${user_name}",
"value": null
}]
},
"content_footer": null,
"audit": {
"creator": "1000",
"timestamp": 1548613800000,
"product": "2",
"channel": "10",
"party": null,
"event": {
"type": null,
"type_id": "0",
"txn_id": "0"
},
"client_key": "pk6781gsfr5"
}
}
I want to replace $CONTENT from template.json with the content under the tag "content" from the content.json file . I have tried with below sed commands:
sed -i 's/$CONTENT/'$(jq -c '.content' sample.json)'/' template.json
I am getting below error:
sed: -e expression #1, char 15: unterminated `s' command
Can someone please help me to get the right sed command (or any other alternative)?

Answer 1

The jq Cookbook has a section on using jq with templates: https://github.com/stedolan/jq/wiki/Cookbook#using-jq-as-a-template-engine
In the present case, the first technique ("Using jq variables as template variables") matches the already-defined template file (except for the dangling comma), so you could for example write:
jq -n --arg CONTENT "$(jq -c .content sample.json)" '
{"subject": "Some subject line", "content": $CONTENT}'
or use the format:
jq -n --arg CONTENT "$(jq -c .content sample.json)" -f template.jq
(I'd only use the .json suffix for files that hold JSON or JSON streams.)

Answer 2

The output from jq contains spaces, you need to quote them to prevent the shell from tokenizing them.
sed -i 's/$CONTENT/'"$(jq -c '.content' sample.json)/" template.json
See further When to wrap quotes around a shell variable?

Answer 3

With GNU sed:
sed '/$CONTENT/{s/.*/jq -c ".content" sample.json/e}'
Replace the entire line with your command and e (GNU only) to execute the command and replace sed's pattern space with the output of the command.