thanks. i think this is what i am looking for. but i'm getting really confused. besides perldoc.com, do you know where i can find more information about whether i should choose $sel->can_read or $sel->can_write? i think my perl script is becoming really confused, because what used to work is now not working anymore. and also, if i am using open2(*Reader, *Writer, $cmd), which filehandle, Reader or Writer, should i use to find out whether the interactive program is waiting for input? or do i use STDIN?
thanks very much. i really appreciate it.