diff --git a/src/script.sh b/src/script.sh
index 3f12b56..09a6656 100644
--- a/src/script.sh
+++ b/src/script.sh
@@ -1,9 +1,7 @@
 #!/bin/sh
 
-# dash does not support pipefail
-# this does not work in `dash script.sh`
-IS_DASH=$(readlink -f "/bin/sh" | grep "dash" || [ $? = 1 ])
-if [ -n "$IS_DASH" ]; then
+if ! (set -o pipefail 2>/dev/null); then
+  # dash does not support pipefail
   set -efx
 else
   set -efx -o pipefail