If you’ve ever pulled your hair attempting to parse JSON using awk/grep/sed,
do your hairline a favor and install jq.
The docs are very good, but to give a non-trivial concrete example, here’s processing JSON output from a Jenkins API:
function poll_jenkins {
url="$JENKINS/job/foo/api/json"
count=0
while [ $count -lt $WAIT_COUNT ]; do
let count=count+1
echo -n "."
sleep 1
response=$(curl -q -S -X GET $url 2>/dev/null)
if [ $(echo $response | jq ".inQueue") = "true" ]; then
continue
fi
last_successful_build=$(echo $response | jq ".lastSuccessfulBuild.number")
last_build=$(echo $response | jq ".lastBuild.number")
if [ "$last_successful_build" = "$last_build" ]; then
LAST_BUILD=$last_build
return
fi
done
}
Retrieving the offer_id from a list of offers:
$ cat offers-2017-07-31.json | jq '[.offers[].offer_id]' | less