Perl in a Nutshell, 2nd Edition

Name

pipe

Synopsis

pipe readhandle, writehandle
                  

Opens a pair of connected pipes. This call is almost always used right before a fork, after which the pipes reader should close writehandle, and the writer should close readhandle. (Otherwise, the pipe won’t indicate end-of-file to the reader when the writer closes it.) 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 standard I/O buffering, so you may need to set $| on your writehandle to flush after each output command, depending on the application. See select filehandle.