Using emacs rmail to read from a different source

Suppose, as in the page referenced above, you are routing probable incoming spam into a file called spam in your mail subdirectory. Here is how you would create an RMAIL format file, SPAM, using that as input so that you could read it just like you do your regular email.

• Type "i" when in emacs rmail mode (eg, when you're reading your regular email). emacs will ask you for an RMAIL format file to read.
• Type the name of the file you wish to create (eg, "SPAM") followed by a carriage return.
• Since the file doesn't exist already, emacs will create it for you, showing you something like this:

      BABYL OPTIONS: -*- rmail -*-
      Version: 5
      Labels:
      Note:   This is the header of an rmail file.
      Note:   If you are seeing it in rmail,
      Note:    it means the file has no messages in it.
  

• We need to add one line to the headers to define the input source. Type "w" to enter write mode on the file. (Recall that unlike in most emacs buffers, what you type in RMAIL mode is usually interpreted as commands.)
• Add the line

      Mail:   /fac/u/username/mail/spam
  

  (where "/fac/u/username/mail/spam" is the full path to the file from which you want to get new messages) at the end of the buffer.
• Save the file ("^X ^S").
• Kill the buffer ("^X k" followed by a carriage return). (This is done because the next time you read this file, emacs will learn where to get its input from.) This will leave you back in your RMAIL buffer.
• Read the new file back in by typing "i" followed by the filename ("SPAM") and a carriage return. (You will always use this method to get to this file.)
• Now when you type "g" messages will be moved from the Unix mail format file SPAM, into the RMAIL format file, SPAM. All your normal mail reading commands will work at this point.