diff --git a/bin/mtm-ssh-vpn b/bin/mtm-ssh-vpn
index dc76bc6..2dfa4a0 100755
--- a/bin/mtm-ssh-vpn
+++ b/bin/mtm-ssh-vpn
@@ -125,8 +125,8 @@ disconnect() {
 	declare ERROR=0
 	if [ -d "${TMP_DIR}" ] && [ "$(find "${TMP_DIR}" -maxdepth 0 -empty -exec echo 1 \;)" == "" ]; then
 		declare -r FILE=${TMP_DIR}/${1}
-		PROFILE=$(basename "${FILE}")
-		PID=$(grep 'PID=' "${FILE}" | sed 's/PID=//')
+		declare -r PROFILE=$(basename "${FILE}")
+		declare -r PID=$(grep 'PID=' "${FILE}" | sed 's/PID=//')
 		if ! kill "${PID}"; then
 			echo "Error: disconnecting vpn ${PROFILE}" >&2
 			ERROR=1
@@ -140,7 +140,7 @@ disconnect_all() {
 	declare ERROR=0
 	if [ -d "${TMP_DIR}" ] && [ "$(find "${TMP_DIR}" -maxdepth 0 -empty -exec echo 1 \;)" == "" ]; then
 		for FILE in "${TMP_DIR}"/*; do
-			PROFILE=$(basename "${FILE}")
+			declare -r PROFILE=$(basename "${FILE}")
 			if [ "$(disconnect "${PROFILE}")" == "1" ]; then
 				ERROR=1
 			fi