Add check for missing elements and work through each array element regardless how it's spelt.

docker_daemon-writer.sh

@@ -1,3 +1,5 @@
+#!/usr/bin/env bash
+# This script is inefficient by design, each setting is applied separately so that any that fail are easily identified and don't affect any of the others.
 
 declare -A DOCKER_OPT
 
@@ -69,15 +71,28 @@ DOCKER_OPT[65]='.["default-addresses-pools"] = [{"base":"172.80.0.0/16","size":2
 
 if [ ! -f /tmp/daemon.json ]
 then
-	touch /tmp/daemon.json
 	echo "{}" > /tmp/daemon.json
 else
 	echo "/tmp/daemon.json exists."
 fi
 
 
-for ((i = 0; i < ${#DOCKER_OPT[@]}; ++i)); do
+# Count through the number of array elements, using ${#
+# looking for one missing.
+for ((i = 1; i < ${#DOCKER_OPT[@]}; ++i)); do
+	if [ -z "${DOCKER_OPT[$i]}" ]; then
+		echo Error: $i missing.
+		exit 1
+	fi
+done
+
+# Work through each array element, using ${!.
+# regardless how it's spelled.
+for i in "${!DOCKER_OPT[@]}"; do
 	OPTION="${DOCKER_OPT[$i]}"
 	jq "${OPTION}" /tmp/daemon.json > /tmp/daemon.json.new && \
 		mv -b /tmp/daemon.json.new /tmp/daemon.json
 done
+
+
+cat /tmp/daemon.json | jq