Appease shellcheck

abra

@@ -170,9 +170,9 @@ sub_cp() {
 	DEST=$2
 
 	SERVICE=$(echo "$SOURCE" | grep -o '^[^:]\+:' || echo "$DEST" | grep -o '^[^:]\+:')
-	SERVICE=$(echo $SERVICE | tr -d ':')
+	SERVICE=$(echo "$SERVICE" | tr -d ':')
 
-	if [ -z $SERVICE ]; then
+	if [ -z "$SERVICE" ]; then
 		echo "$(tput setaf 1)ERROR: Can't find SERVICE in either SRC or DEST$(tput sgr0)"
 		echo ""
 		echo "Usage: $PROGRAM_NAME cp SERVICE:SRC_PATH DEST_PATH"
@@ -183,7 +183,7 @@ sub_cp() {
 	CONTAINER=$(docker container ls --format "table {{.ID}},{{.Names}}" \
 		| grep "${STACK_NAME}_${SERVICE}" | cut -d',' -f1)
 
-	if [ -z $CONTAINER ]; then
+	if [ -z "$CONTAINER" ]; then
 		echo "$(tput setaf 1)ERROR: Can't find a ${STACK_NAME}_${SERVICE}$(tput sgr0)"
 		exit
 	fi