-offset=$(grep -na -m1 "^MARKER:$" ${SDK_FILE} | cut -d':' -f1)
-eval $(head -n $offset ${SDK_FILE} | grep ^DEFAULT_INSTALL_DIR= )
+offset=$(grep -na -m1 "^MARKER:$" "${SDK_FILE}" | cut -d':' -f1)
+eval $(head -n $offset "${SDK_FILE}" | grep ^DEFAULT_INSTALL_DIR= )