diff --git a/runtime/ftplugin/bash.vim b/runtime/ftplugin/bash.vim
index a3d01fc..7bd9787 100644
--- a/runtime/ftplugin/bash.vim
+++ b/runtime/ftplugin/bash.vim
@@ -11,21 +11,10 @@
   finish
 endif
 
+unlet! b:is_sh
+unlet! b:is_kornshell
 let b:is_bash = 1
-if exists("b:is_sh")
-  unlet b:is_sh
-endif
-if exists("b:is_kornshell")
-  unlet b:is_kornshell
-endif
 
-" Setting 'filetype' here directly won't work, since we are being invoked
-" through an autocommand.  Do it later, on the BufWinEnter event.
-augroup bash_filetype
-  au BufWinEnter * call SetBashFt()
-augroup END
+runtime! ftplugin/sh.vim ftplugin/sh_*.vim ftplugin/sh/*.vim
 
-func SetBashFt()
-  au! bash_filetype
-  set ft=sh
-endfunc
+" vim: ts=8