diff --git a/.githooks/post-checkout b/.githooks/post-checkout
index db149ad..5ee5dca 100755
--- a/.githooks/post-checkout
+++ b/.githooks/post-checkout
@@ -31,7 +31,7 @@ if [ -f $CHECKOUT_HISTORY_FILE ]; then
             for opkg_c in "${opkg_commands[@]}"; do
                 # check for   empty lines
                 echo "CCC=${opkg_c}CCC"
-                if grep -qE '^\s*$' <<< "${opkg_c}"; then
+                if grep -qE '^[[:space:]]+$' <<< "${opkg_c}"; then
                     continue
                 fi
                 echo "DDD=${opkg_c}DDD"