Following instructions here:-
Using the whole buffer If you are programming using an interpreted language, such as Perl or Python, or a shell script, such as BASH, you might want to run your entire program through the interpreter. To do that, use
mark-whole-buffer), then use
M-|to send all of the buffer text to the interpreter.
As a simple test I created a new buffer which consisted of:
C-x h followed by
M-| but /test did not get created.
What am I missing?