I'm new to this, but can somebody explain this behavior to me? Thanks! bash-3.2$ (echo a; echo b; sleep 1; echo c) | /tmp/bar.py line: a line: b a b line: c c bash-3.2$ (echo a; echo b; echo c) | /tmp/bar.py line: a line: b line: c bash-3.2$ cat /tmp/bar.py #!/usr/bin/env python from twisted.internet import reactor from twisted.protocols.basic import LineOnlyReceiver from twisted.internet.stdio import StandardIO class MyLineOnlyReceiver(LineOnlyReceiver): delimiter = '\n' def lineReceived(self, line): self.transport.write(line+self.delimiter) print "line:", line def connectionLost(self, why): LineOnlyReceiver.connectionLost(self, why) reactor.callWhenRunning(lambda:reactor.stop()) if __name__ == '__main__': StandardIO(MyLineOnlyReceiver()) reactor.run() bash-3.2$ port info 'py25-twisted' py25-twisted @8.0.1 (python, devel, net) Twisted is an event-driven networking framework written in Python. Twisted supports TCP, UDP, SSL/TLS, multicast, Unix sockets, a large number of protocols (including HTTP, NNTP, SSH, IRC, FTP, and others), and much more. Homepage: http://www.twistedmatrix.com/ Library Dependencies: python25, py25-zopeinterface Maintainers: stechert@macports.org akitada@macports.org openmaintainer@macports.org bash-3.2$ python -V Python 2.5.4 bash-3.2$ uname -a Darwin d72.cozy.org 9.6.0 Darwin Kernel Version 9.6.0: Mon Nov 24 17:37:00 PST 2008; root:xnu-1228.9.59~1/RELEASE_I386 i386 i386 bash-3.2$