Hi,
Try:
export EDITOR=vi
and the hit the ESC key and used the vi navigation keys to navigate the commands.
Also, you should read the man page for ksh.
Here is an excerpt from the man page:
vi Editing Mode
There are two typing modes. Initially, when you enter a
command you are in the input mode. To edit, enter control
mode by typing ESC (033) and move the cursor to the point
needing correction and then insert or delete characters or
words as needed. Most control commands accept an optional
repeat count prior to the command.
When in vi mode on most systems, canonical processing is
initially enabled and the command will be echoed again if
the speed is 1200 baud or greater and it contains any con-
trol characters or less than one second has elapsed since
the prompt was printed. The ESC character terminates canoni-
cal processing for the remainder of the command and the user
can then modify the command line. This scheme has the
advantages of canonical processing with the type-ahead echo-
ing of raw mode.
If the option viraw is also set, the terminal will always
have canonical processing disabled. This mode is implicit
for systems that do not support two alternate end of line
delimiters, and may be helpful for certain terminals.
-Joe