diff --git a/autoload/fugitive.vim b/autoload/fugitive.vim
index edf75ed..06f06de 100644
--- a/autoload/fugitive.vim
+++ b/autoload/fugitive.vim
@@ -1315,12 +1315,7 @@ function! fugitive#FileWriteCmd(...) abort
       let old_mode = executable(s:Tree(dir) . file) ? '100755' : '100644'
     endif
     let info = old_mode.' '.sha1.' '.commit."\t".file[1:-1]
-    call writefile([info],tmp)
-    if s:winshell()
-      let error = s:System('type '.s:gsub(tmp,'/','\\').'|'.s:Prepare(dir, 'update-index', '--index-info'))
-    else
-      let error = s:System(s:Prepare(dir, 'update-index', '--index-info').' < '.tmp)
-    endif
+    let error = system(s:Prepare(dir, 'update-index', '--index-info'), info . "\n")
     if v:shell_error == 0
       setlocal nomodified
       if exists('#' . autype . 'WritePost')