Readline Bare Essentials
------------------------

   In order to enter characters into the line, simply type them.  The
typed character appears where the cursor was, and then the cursor moves
one space to the right.  If you mistype a character, you can use your
erase character to back up and delete the mistyped character.

   Sometimes you may miss typing a character that you wanted to type,
and not notice your error until you have typed several other
characters.  In that case, you can type <C-b> to move the cursor to the
left, and then correct your mistake.  Afterwards, you can move the
cursor to the right with <C-f>.

   When you add text in the middle of a line, you will notice that
characters to the right of the cursor are `pushed over' to make room
for the text that you have inserted.  Likewise, when you delete text
behind the cursor, characters to the right of the cursor are `pulled
back' to fill in the blank space created by the removal of the text.  A
list of the basic bare essentials for editing the text of an input line
follows.

<C-b>
     Move back one character.

<C-f>
     Move forward one character.

<DEL>
     Delete the character to the left of the cursor.

<C-d>
     Delete the character underneath the cursor.

Printing characters
     Insert the character into the line at the cursor.

<C-_>
     Undo the last thing that you did.  You can undo all the way back
     to an empty line.