a2ps -Phockney textfile is the command to print a postscript file to the printer hockney.
Using pipes, print all lines of list1 and list2 containing the letter 'p', sort the result, and print to the printer hockney.
% cat list1 list2 | grep p | sort | a2ps -Phockney
M.Stonebank@ee.surrey.ac.uk, © November, 2002