diff --git a/autoload/do.vim b/autoload/do.vim
new file mode 100644
index 0000000..0c78d93
--- /dev/null
+++ b/autoload/do.vim
@@ -0,0 +1,11 @@
+" Save, call isort on, then reload a python file.
+function! do#isort()
+  if &filetype !=# 'python'
+    echohl ErrorMsg
+    echomsg 'isort only supports python files'
+    echohl None
+  endif
+  write!
+  call system('isort '.expand('%:p'))
+  edit!
+endfunction
diff --git a/plugin/commands.vim b/plugin/commands.vim
new file mode 100644
index 0000000..c1e034f
--- /dev/null
+++ b/plugin/commands.vim
@@ -0,0 +1 @@
+command! ISort call do#isort()