diff --git a/2018/burton2/mkkeywords.sh b/2018/burton2/mkkeywords.sh
index 0aeaa26c9..90078b568 100755
--- a/2018/burton2/mkkeywords.sh
+++ b/2018/burton2/mkkeywords.sh
@@ -1,3 +1,3 @@
-#!/bin/sh
+#!/usr/bin/env bash
 awk '/^[^$]/{l=length;m=m>l?m:l;a[l]=a[l]$1}
-     END{printf"\"";for(i=1;i<=m;++i)printf" "a[i];print"\""}' $*
+     END{printf"\"";for(i=1;i<=m;++i)printf" "a[i];print"\""}' "$@"