# example from page 63
(read; print -r "$REPLY") |&   # Begin co-process 1.
exec 5>&p                      # Move to descriptor 5.
(read; print -r "$REPLY") |&   # Begin co-process 2.
exec 6>&p                      # Move to descriptor 6.
date >&6                       # Date to co-process 2.
print -u5 foobar               # Print to co-process 1.
exec 3<&p                      # Move input of both 
                               # co-processes to 3.
read -ru3 line                 # Read from co-process.
print -r "$line"               # Display the line.
read -ru3 line                 # Read another line.
print -r "$line"               # Display it.