DaWei

That presumes synchronized read/write or adequate buffering, both of which are implementation dependent. Have you established that a hand-implementation of:

$ rankmirrors current > current.new

is equivalent to:

rankmirrors $mirror > $mirror

??

__________________
Abstraction doesn't make it impossible to write bad code; it makes it possible to write superior code.
Contributor's Corner: Grumpy on C++ Exceptions DaWei on Pointers