Although it is always possible to fix errors by retyping
the entire erroneous line with the 'c' command, it is
usually much faster to make small changes within
a line. The editor allows this with the 's' (substitute)
will change a line previously reading
by replacing the string 'abc' in the line with the string 'def'.
In this directory is a file 'pres' with one line that says
'harry' where it should say 'george'. Fix it using the
substitute command to change 'harry' into 'george'. You
should use the 'p' command to print the line before and
after, checking that you did it correctly. Then
rewrite the file and type 'ready'.