1 files changed, 1 insertions, 1 deletions
diff --git a/upslak.sh b/upslak.sh
index 0a82690..c36071d 100644
--- a/upslak.sh
+++ b/upslak.sh
@@ -1106,7 +1106,7 @@ if [ -f "${EXTENSION}" ]; then
       # User already mounted the USB linux partition; remove mountpoint:
       EXTENSION="${EXTENSION#$EXTMNT}"
     fi
-elif [ "$(dirname ${EXTENSION})" == "." ]; then
+elif [ -n "${EXTENSION}" && "$(dirname ${EXTENSION})" == "." ]; then
   # Containerfile was provided without leading slash, add one:
   EXTENSION="/${EXTENSION}"
 fi