[barrkel]

The "Windows-culture" way of making something programmer-accessible is to provide an API, usually using COM (preferably with IDispatch support for ease of use and scriptability), or these days .NET. Such an interface is richer than one can normally get using the command-line, which is essentially forced to multiplex possibly multiple threads of control and interaction with many program "objects" through a single bidirectional pipe.

The bidirectional pipe has other benefits, of course; it's easily remoted using ssh or even straight TCP, rather than needing the complexity of DCOM (made easier using IDispatch and variants/type/etc. with built-in remoting support).

[phugoid]

Are you saying that a single bidirectional pipe is the only way that two linux programs can communicate?

[barrkel]

No, but that's the most obvious way to wrap a GUI around a command-line app.