fix portability issues with $ in double quotes

diff --git a/t/t0021-conversion.sh b/t/t0021-conversion.sh
index 8fc39d77cec6168dae930beef785597dace24aa3..6cb8d60ea2649495c0e3c8bbb8b7cc75c36799b7 100755 (executable)
--- a/t/t0021-conversion.sh
+++ b/t/t0021-conversion.sh
@@ -4,7 +4,8 @@ test_description='blob conversion via gitattributes'
 
 . ./test-lib.sh
 
-cat <<\EOF >rot13.sh
+cat <<EOF >rot13.sh
+#!$SHELL_PATH
 tr \
   'abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ' \
   'nopqrstuvwxyzabcdefghijklmNOPQRSTUVWXYZABCDEFGHIJKLM'