2.11BSD/src/share/learn/editor/L37.2b

#print
Now edit file "text" and change the "cat" on every line
into "mouse".  Then rewrite the file and type "ready".
#create Ref
domestic mouse
alley mouse
persian mouse
angora mouse
wildmouse
#create text
domestic cat
alley cat
persian cat
angora cat
wildcat
#user
#cmp text Ref
#log
#next
37.2c 5