Changing a whole line with the 'c' command is a slow way
to work when you only want to change a few letters. The 's' (substitute)
command changes the letters within a line. For example, the command
will change a line reading
by replacing the string 'abc' with 'def'. Try the following sequence which
alters the first line of the file 'test' within this directory:
Four score and seven years ago our
fathers brought forth ...
Four score and seven months ago our
fathers brought forth ...