jq — JSON Processing on the Command Line¶
JSON is everywhere — APIs, configuration files, logs. jq is like sed/awk for JSON — it filters and transforms data right from the terminal.
Basics¶
sudo apt install jq echo ‘{“name”:”test”,”value”:42}’ | jq ‘.’
Filtering¶
curl -s api/data | jq ‘.results[0].name’ jq ‘.[] | .email’ users.json jq ‘.[] | select(.age > 30)’ users.json jq ‘.[] | {name: .name, email: .email}’ users.json
Transformation¶
jq ‘{hostname: .name, cores: .cpu}’ server.json jq -r ‘.[] | [.name, .email] | @csv’ users.json jq -s ‘.[0] * .[1]’ defaults.json overrides.json
Aggregation¶
jq ‘.users | length’ data.json jq ‘[.[] | .price] | {min: min, max: max, avg: (add / length)}’ products.json jq ‘[.[] | .category] | unique’ products.json
Examples¶
curl -s ‘https://api.github.com/users/torvalds/repos’ | jq ‘.[] | {name, stars: .stargazers_count}’ kubectl get pods -o json | jq ‘.items[] | select(.status.phase != “Running”) | .metadata.name’ cat app.log | jq -c ‘select(.level == “error”) | {time: .timestamp, msg: .message}’
jq is Essential¶
For API and JSON data, jq dramatically speeds up your workflow.