4.3BSD-UWisc/lib/learn/editor/L32.2b

#print
Or, to take another example, the command
  s/h./ar/
would turn the word "that" into "tart": the '.' matches
the 'a'.  What would that command change the
word "what" into?  Reply "answer WORD" where WORD
is what the substitute command would produce.
#copyin
#user
#uncopyin
#match wart
#log
#next
32.2c 5