the magic of serial monitor

Hi, sorry for the cross posting, but not having received any answer on this: Arduino Forum I re-propose the issue here in more general terms.

Basically, on Mac OS X 10.7.2 (Lion) I can use my Arduino UNO without any problem, issues arise when I attempt to communicate with the Serial Port with something that is not the IDE Serial Monitor.

The bash will fail, PHP serial communication will hang etc…
The thing that bug me is that, if I have the IDE running the Serial Monitor, I can magically communicate with the serial port via bash or PHP, as soon as I close the Serial Monitor my Mac is unable to communicate successfully with the serial port.

Now, I understand that most of this may be down to the Arduino UNO auto reset feature and I know I can disable adding a resistor on pin reset/GND… but I'd like to avoid to have to hang things on the Arduino UNO just to experiment serial port communication, also because if the Serial Monitor can make the Serial Port working why cannot the operating system alone?

There is any way/suggestion to keep the serial port working without have to keep open the IDE Serial Monitor?