[sed] add missing opening bracket [ to a json file

 

You want to wrap your JSON file content in an array by adding an opening [ at the very beginning and a closing ] at the very end (assuming your current file is missing these brackets). Here's how you can do it with sed (or sed + echo for the end bracket).

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Add an opening [ at the beginning of the file:

sed -i '1s/^/[/' filename.json

Explanation:

• 1s/^/[/' → On the first line (1), substitute the start of the line (^) with [.

• -i → Edit the file in place.

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Add a closing ] at the end of the file:

You can do this with sed as well:

sed -i -e '$s/$/]/' filename.json

Explanation:

• $s/$/]/ → On the last line ($), append ] at the end of the line.

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Combined one-liner:

sed -i '1s/^/[/' filename.json && sed -i '$s/$/]/' filename.json

This will wrap your JSON content in an array, which fixes the missing brackets issue.

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If your JSON file has multiple top-level objects separated by commas, this will work fine. If they are not separated by commas, you may need to insert commas between objects too.

I can give you a safe version that automatically adds commas between objects if you want. Do you want me to do that?