Review shell scripts

Signed-off-by: Nikolaos Karaolidis <nick@karaolidis.com>

lib/runtime/merge/key-value.sh

@@ -1,13 +1,13 @@
-SOURCE_FILE=$(realpath -m "$1")
-TARGET_FILE=$(realpath -m "$2")
+source=$(realpath -m "$1")
+target=$(realpath -m "$2")
 
-if [[ -f "${TARGET_FILE}" ]]; then
-  TEMP_FILE=$(mktemp)
-  awk -F '=' 'NR==FNR{a[$1]=$0;next}($1 in a){$0=a[$1]}1' "${SOURCE_FILE}" "${TARGET_FILE}" > "${TEMP_FILE}"
-  mv "${TEMP_FILE}" "${TARGET_FILE}"
+if [[ -f "$target" ]]; then
+  temp=$(mktemp)
+  awk -F '=' 'NR==FNR{a[$1]=$0;next}($1 in a){$0=a[$1]}1' "$source" "$target" > "$temp"
+  mv "$temp" "$target"
 else
-  mkdir -p "$(dirname "${TARGET_FILE}")"
-  cp "${SOURCE_FILE}" "${TARGET_FILE}"
+  mkdir -p "$(dirname "$target")"
+  cp "$source" "$target"
 fi
 
-echo "Configuration file ${TARGET_FILE} has been updated."
+echo "Configuration file $target has been updated."