// Create file handles for standard input and output
FileHandleRef  stdIn = fn FileHandleWithStandardInput
FileHandleRef stdOut = fn FileHandleWithStandardOutput

// Continuously read from standard input…
while (YES)
  CFDataRef availableData = fn FileHandleAvailableData( stdIn )
  if ( fn DataLength( availableData ) == 0 )
    break  // End of input
  end if
  // … and write to standard output
  fn FileHandleWriteData( stdOut, availableData, NULL )
wend