Think of it this way... Process 2 only prints out lines which it knows that both process 1 and process 2 have. This is then relayed to process 3. So process 3 has a list of lines, that have all been known to match at least in the other two processes, and a list of other lines. The moment it finds a line that equals - it's done - we know it's in all 3 lists.

The pipelining structure basically filters anything that is definately not a match in the transition from 1 to 2. Then it filters out anything that is definately not a match between 2 and 3. The first thing that results is the answer.

For an example of a bidirectional TCP/IP type thing, without the IO::Socket interface (but you should be able to cope), see perlipc.

But I stress that bidirectionality is not necessary =)

-nuffin
zz zZ Z Z #!perl

In reply to Re^3: sockets and such in Perl by nothingmuch
in thread sockets and such in Perl by scotchfx

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