I’m trying to use jq to get an array from a json object and I need to remove the last three elements of this array. So this is what I did so far:
echo '{ "tags": [ "2.9.7", "2.9.8", "2.9.9", "2.9.10", "2.9.11", "2.9.12" ]}' | jq -r '.tags | sort[:3][]'
gives me 2.9.10 2.9.11 2.9.12, but need it the other way round. These values should be removed, so the result should be:
2.9.7 2.9.8 2.9.9
>Solution :
Start the index counter at the third-last element [-3, and go until the end :]:
… | jq -r '.tags | sort[-3:][]'
2.9.7
2.9.8
2.9.9
Watch out, however, as you are sorting strings here, where 2.9.12 will be sorted before 2.9.7. If you want to sort the array by version numbers (structured as seen), split them at the dot into an array, convert the items into numbers, and sort by that:
… | jq -r '.tags | sort_by(split(".") | map(tonumber))[:3][]'
2.9.7
2.9.8
2.9.9