pipe
pipe - open a pair of connected filehandles
pipe READHANDLE,WRITEHANDLE
Opens a pair of connected pipes like the corresponding system call.
Note that if you set up a loop of piped processes, deadlock can occur
unless you are very careful. In addition, note that Perl's pipes use
stdio buffering, so you may need to set $| to flush your WRITEHANDLE
after each command, depending on the application.
See open2, open3, and ``Bidirectional Communication''
for examples of such things.