Shell script for adding an increasing ID as a first key of an object inside an JSON array.

script.sh

#!/bin/zsh

FILE_PATH="data.json"
DATA=$(cat "$FILE_PATH")
REVERSE_ORDER=$(jq 'reverse' <<<"$DATA")
DATA_LENGTH=$(echo "$REVERSE_ORDER" | jq '. | length')

for ((INDEX = 0; INDEX < DATA_LENGTH; INDEX++)); do
  REVERSE_ORDER=$(jq --argjson id "$INDEX" '.['"$INDEX"'] += { "id": ($id+1) }' <<<"$REVERSE_ORDER")
done

SORT_KEYS=$(jq '[.[] | { id, keyTwo, keyThree, keyFour }]' <<<"$REVERSE_ORDER")
echo "$SORT_KEYS" >"$FILE_PATH"