#print Suppose that we really do want to interchange the contents of the files "dick" and "jane". One way to do it is to move the contents of "dick" into some temporary file, then move "jane" onto "dick" (which of course clobbers the old contents of "dick", but we saved them already), then finally to move the temporary copy of "dick" to "jane". There are two files named "dick" and "jane" in this directory. Interchange their contents, then type "ready". #create Ref short file for dick #create dick short file for dick #create jane another file for jane #create Ref1 another file for jane #user cmp -s jane Ref && cmp -s dick Ref1 #log