Adding lines to a linux file using bash script [closed] - linux

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I want to add lines '{"index":{"_id":$number_of_id}}' to my file name ss.josn before each json object (which is a line)
cat ss.json
input example:
{"msisdn":"255742005249","subscription_date":"2021-05-26T16:41:40.467Z","optout_date":"2022-01-03T19:12:59.808Z","total_charged_amount":1300}
{"msisdn":"255742009077","subscription_date":"2019-12-31T22:00:00.000Z","optout_date":"2022-01-09T14:08:00.282Z","total_charged_amount":3370}
{"msisdn":"255742009703","subscription_date":"2019-12-31T22:00:00.000Z","optout_date":"2022-01-01T12:34:02.104Z","total_charged_amount":400}
Desired output:
{"index":{"_id":1}}
{"msisdn":"255742005249","subscription_date":"2021-05-26T16:41:40.467Z","optout_date":"2022-01-03T19:12:59.808Z","total_charged_amount":1300}
{"index":{"_id":2}}
{"msisdn":"255742009077","subscription_date":"2019-12-31T22:00:00.000Z","optout_date":"2022-01-09T14:08:00.282Z","total_charged_amount":3370}
{"index":{"_id":3}}
{"msisdn":"255742009703","subscription_date":"2019-12-31T22:00:00.000Z","optout_date":"2022-01-01T12:34:02.104Z","total_charged_amount":400}

Answer 1

If you can ensure that each line is a json struct and you don't have multiline case, a script like this should do the job:
#!/bin/bash
_id=0
while read -r line; do
echo "{"index":{"_id":$_id}}" >> result.json
echo $line >> result.json
_id=$((_id+1))
done < ss.json
Maybe not the most elegant option, but you will have a result.json file with your desired output.