System Information

jq: 1.7

Pick

• Following command works correctly as expected:

jq 'pick(.id,.title,.webpage_url,.channel,.duration_string,.upload_date)' *.info.json

{"id": "uO8Sn0Xch1s","title": "A transformative new way of classifying foods 🍔🍕🍟 BBC","webpage_url": "https://www.youtube.com/watch?v=uO8Sn0Xch1s","channel": "BBC","duration_string": "4:19","upload_date": "20210701"}

Pick and Append

$ Date=$(date +%Y-%m-%d)$ jq 'pick(.id,.title,.webpage_url,.channel,.duration_string,.upload_date)' *.info.json \  | jq --arg Date="$Date" '. += {"date": $Date}'

{"id": "uO8Sn0Xch1s","title": "A transformative new way of classifying foods 🍔🍕🍟 BBC","webpage_url": "https://www.youtube.com/watch?v=uO8Sn0Xch1s","channel": "BBC","duration_string": "4:19","upload_date": "20210701"}

Issue

1. Pick and Append produces same output as Pick and is not appending date. Why and how can I correct this?
2. also tried + instead of +=, both didn't work (but should work as per Reference 2)

Expected Output

{"id": "uO8Sn0Xch1s","title": "A transformative new way of classifying foods 🍔🍕🍟 BBC","webpage_url": "https://www.youtube.com/watch?v=uO8Sn0Xch1s","channel": "BBC","duration_string": "4:19","upload_date": "20210701","date": "2024-05-10"}

Reference

• How to add a field to a JSON object with the jq command? - Stack Overflow
• Add new element to existing JSON array with jq - Stack Overflow