diff --git a/z.lua b/z.lua
index d0c1d94..dcb2e6b 100644
--- a/z.lua
+++ b/z.lua
@@ -379,6 +379,22 @@ function os.path.subdir(basename, subname)
 end
 
 
+-----------------------------------------------------------------------
+-- check single name element
+-----------------------------------------------------------------------
+function os.path.single(path)
+	if string.match(path, '/') then
+		return false
+	end
+	if windows then
+		if string.match(path, '\\') then
+			return false
+		end
+	end
+	return true
+end
+
+
 -----------------------------------------------------------------------
 -- expand user home
 -----------------------------------------------------------------------
@@ -415,8 +431,12 @@ function os.interpreter()
 		return nil
 	end
 	local lua = arg[-1]	
-	if lua == 'lua' then
-		return os.path.which('lua')
+	if os.path.single(lua) then
+		local path = os.path.which(lua)
+		if not os.path.isabs(path) then
+			return os.path.abspath(path)
+		end
+		return path
 	end
 	return os.path.abspath(lua)
 end