stdin/stdout

["Jack O'Connor" <oconnor663@gmail.com>]

Is there any way in Emacs to read standard input into a buffer or to
send the contents of a buffer to the standard output (particularly
both with editing in between)? I'm interested in being able to do
things like the following:

decrypt file.crypt | emacs | encrypt > file2.crypt
                     ---or perhaps---
curl some-website-with-code.com | emacs | python
                    ---or even just---
emacs < file.txt > edited_file.txt

Thanks very much for your help.

- Jack O'Connor