Ignore Unparseable JSON with jq

Assuming that each log entry is exactly one line, you can use the -R or --raw-input option to tell jq to leave the lines unparsed, after which you can prepend fromjson? | to your filter to make jq try to parse each line as JSON and throw away the ones that error.

I have log stream where some messages are in json format. I want to pipe the json messages through jq, and just echo the rest.

The json messages are on a single line.

Solution: use grep and tee to split the lines in two streams, those starting with "^{" pipe through jq and the rest just echo to terminal.

kubectl logs -f web-svjkn | tee >(grep -v "^{") | grep "^{" | jq .

or

cat logs | tee >(grep -v "^{") | grep "^{" | jq .

Explanation: tee generates 2nd stream, and grep -v prints non json info, 2nd grep only pipes what looks like json opening bracket to jq.