diff --git a/job.c b/job.c
index 2df0eba..11ec818 100644
--- a/job.c
+++ b/job.c
@@ -2561,7 +2561,11 @@ construct_command_argv_internal (char *line, char **restp, const char *shell,
 
   /* See if it is safe to parse commands internally.  */
   if (shell == 0)
-    shell = default_shell;
+    {
+      shell = default_shell;
+      if (shellflags == 0)
+	shellflags = "-c";
+    }
 #ifdef WINDOWS32
   else if (strcmp (shell, default_shell))
   {