Bkgnd process that returns immediately

[Mark Powell]

A 2005 thread (from Brian, Xavier, Chipp, et. al) talked about
re-direction to achieve a non-blocking shell call, using 

 get shell("mycommand > mylogfile.log &")

My brain cannot get this to work.  Let's say I want Rev to start
"C:\blah.html" using shell(), and then continue executing downstream Rev
handlers.  I've tried variations of

 get shell("start > C:\blah.html &")

and

 get shell("start > C:\shellTemp.txt &")

      where shellTemp.text contains 
       C:\blah.html
      among other variations

but nothing works.  The following 

  get shell("start C:\blah.html &")

does work, but it is blocking.

I understand the ampersand performs a handoff but am ignorant of the
overall sequence of events.  What am I doing wrong?  

Mark