Commodore 128D - Page 216

Using Control
Characters for
Line Editing
By using the line-editing control characters listed in Table 13-1, you
can move the cursor left and right to insert and delete characters in
the middle of a command line. In this way you do not have to retype
everything to the right of your correction.
In the following sample example, the user mistypes PIP, and CP/M
3.0 returns an error message. The user recalls the erroneous com
mand line by pressing CTRL-W and corrects the error (the underbar
character represents the cursor):
(PIP mistyped)
(CTRL-W recalls the line)
u
u
u
POP?
A>P0PA: = B:V
:V
(CTRL-B moves cursor to beginning of line)
(CTRL-F moves cursor to right)
(CTRL-G deletes error)
(type I corrects the command name)
A>POPA: = B:
A>P0PA: = B:V
A>P£A: = B:V
A>PIPA: = B:V
After the command line is corrected, the user can press RETURN
even though the cursor is in the middle of the line. A RETURN key
stroke, (or one of the equivalent control characters) not only exe
cutes the command, but also stores the command in a buffer so that
you can recall it for editing or reexecution by pressing CTRL-W.
When you insert a character in the middle of a line, characters to the
right of the cursor move to the right. If the line becomes longer than
your screen is wide, characters disapper off the right side of the
screen. These characters are not lost. They reappear if you delete
characters from the line or if you press CTRL-E when the cursor is in
the middle of the line. CTRL-E moves all characters to the right of the
cursor to the next line on the screen.
Table 13-1 gives a complete list of line-editing control characters for
the CP/M 3.0 system on the Commodore 128.
Table 13-1. CP/M 3.0 Line-editing Control Characters
Character Meaning
CTRL-Aor
SHIFT-LEFT
CURSOR
CTRL-B
Moves the cursor one character to the left.
Moves the cursor to the beginning of the com
mand line without having any effect on the con
tents of the line. If the cursor is at the beginning,
CTRL-B moves it to the end of the line.
208 USING CP/M MODE—Using the Console and Printer in CP/M 3.0