[FASTCGI] Kill fastcgi process

[Matt]

"Bryan White" writes...
["When I have a new version is install by just moving the new version
into place.  Note, a 'mv' is atomic.  A 'cp' could cause all sorts of
problems."]
So is it better than to use mv to overwrite a file then to use cp to overwrite the file? Whats the difference? What is the shell/OS
doing different for a move Vs a copy?