title: Sublime Text: run code in a new file without saving to disk and the default language setting for a new file
body: <p>I am using Sublime Text Editor for Python development. If I create a new file by Ctrl + N, the default language setting for this file is Plain Text, so how to change the default language setting for the new file to be Python ?</p>
  
  <p>Another question :If I write some code in the new file and have not save it to disk, it is impossible to run it and get the running result, is there a solution to remove this restriction so that we can run code in the new file without saving it to disk first?</p>