fix _exists

diff --git a/acme.sh b/acme.sh
index ba4688cf3791e584d6ef91ce1885f29399ca8bf0..280cb41590bf92bd65a2ad58355978b41bf8ae90 100755 (executable)
--- a/acme.sh
+++ b/acme.sh
@@ -249,7 +249,7 @@ _exists() {
   fi
   if command >/dev/null 2>&1; then
     command -v "$cmd" >/dev/null 2>&1
-  elif which >/dev/null 2>&1; then
+  elif which ls >/dev/null 2>&1; then
     which "$cmd" >/dev/null 2>&1
   fi
   ret="$?"