.bp
.MH "Screen Editor Control Characters"
.sp
(Files can be edited with control characters only
when you are in overlay mode, which you can enter
with the 'v' command.  A control-v will exit overlay
mode and put you back into command mode.  While
in command mode you can use these characters to
edit your command.)
.sp
.ti [in]
.ta 11
.ul
Character[tc]Action
.sp
.in +10
.HI 10 control-a
Toggle insert mode.  The status of the insertion indicator
is inverted.
Insert mode, when enabled, causes characters typed to be
inserted at the current cursor position in the line
instead of overwriting the characters that were there
previously.  When insert mode is in effect, "INSERT" appears
in the status line.
.HI 10 control-b
Scan right and erase.  The current line is scanned from the
current
cursor position to the right margin until an occurrence of the
next character typed is found.  When the character is found, all
characters from the current cursor position up to (but not including)
the scanned character are deleted and the remainder of the line
is moved to the left to close the gap.  The cursor is left in
the same column which is now occupied by the scanned character.
If the line to the right of the cursor does not contain the character
being sought, the terminal's bell is sounded.
'Se' remembers the last character that was scanned using this
or any of the other scanning keys;
if control-b is hit twice in a row, this remembered character is
used instead of a literal control-b.
.HI 10 control-c
Insert blank.  The characters at and to the right of
the current cursor position are moved to the right one column
and a blank is inserted to fill the gap.
.HI 10 control-d
Cursor up.  The effect of this key depends on 'se's current
mode.  When in command mode, the current line pointer is moved
to the previous line without affecting the contents of the command
line.  If the current line pointer is at line 1, the last line
in the file becomes the new current line.
In overlay mode (viz. the "v" command), the cursor is
moved up one line while remaining in the same column.
In append mode, this key is ignored.
.HI 10 control-e
Tab left.  The cursor is moved to the nearest tab stop
to the left of its current position.
.HI 10 control-f
"Funny" return.  The effect of this key depends on the
editor's current mode. In command mode, the current command line is entered
as-is, but is not erased upon completion of the
command; in append mode, the current line is duplicated; in
overlay mode (viz. the "v" command), the current line is restored
to its original state and command mode is reentered (except if
under control of a global prefix).
.HI 10 control-g
Cursor right.  The cursor is moved one column to the right.
.HI 10 control-h
Cursor left.  The cursor is moved one column to the left.
Note that this [ul does not]
erase any characters; it simply moves the cursor.
.HI 10 control-i
Tab right.
The cursor is moved to the next tab stop to the right of its current
position.
.HI 10 control-k
Cursor down.  As with the control-d key, this key's effect depends
on the current editing mode.  In command mode,  the current line pointer
is moved to the next line without changing the contents of the command
line. If the current line pointer is at the last line in the file,
line 1 becomes the new current line.  In overlay mode (viz. the
"v" command), the cursor is moved down one line while remaining in the
same column.  In append mode, control-k has no effect.
.HI 10 control-l
Scan left.  The cursor is positioned according to the character
typed immediately after the control-l.  In effect, the current line is
scanned, starting from the current cursor position and moving left,
for the first occurrence of this character.  If none is found before
the beginning of the line is reached, the scan resumes with the
last character in the line.  If the line does not contain the character
being looked for, the message "NOT FOUND" is printed in the status line.
'Se' remembers the last character
that was scanned for using this key; if the control-l is hit twice in
a row, this remembered character is searched for instead of a literal
control-l.
Apart from this, however, the character typed after control-l is taken
literally, so 'se's case conversion feature does not apply.
.HI 10 control-m
Newline.  This key is identical to the NEWLINE key
described below.
.HI 10 control-n
Scan left and erase.
The current line is scanned from the current cursor position to the
left margin until an occurrence of the next character typed is found.
Then that character and all characters to its right up to
(but not including) the character under the cursor are erased.
The remainder of the line, as well as the cursor are moved to the
left to close the gap.  If the line to the left of the cursor
does not contain the character being sought, the terminal's bell is
sounded.
As with the control-b key,
if control-n is hit twice in a row, the last character scanned for is
used instead of a literal control-n.
.HI 10 control-o
Skip right.  The cursor is moved to the first position beyond
the current end of line.
.HI 10 control-p
Interrupt.  If executing any command except "a", "c", "i" or
"v", 'se' aborts the command and reenters command mode.  The command
line is not erased.
.HI 10 control-q
Fix screen.  The screen is reconstructed from 'se's internal
representation of the screen.
.HI 10 control-r
Erase right.  The character at the current cursor position
is erased and
all characters to its right are moved left one position.
.HI 10 control-s
Scan right.  This key is identical to the control-l key
described above, except that the scan proceeds to the right from
the current cursor position.
.HI 10 control-t
Kill right.  The character at the current cursor position
and all those to its right are erased.
.HI 10 control-u
Erase left.  The character to the left of the current cursor
position is deleted and all characters to its right are moved
to the left to fill the gap.  The cursor is also moved left one
column, leaving it over the same character.
.HI 10 control-v
Skip right and terminate.  The cursor is moved to the current
end of line and the line is terminated.
.HI 10 control-w
Skip left.  The cursor is positioned at column 1.
.HI 10 control-x
Insert tab.  The character under the cursor is moved
right to the next tab stop; the gap is filled with blanks.
The cursor is not moved.
.HI 10 control-y
Kill left.  All characters to the left of the cursor are
erased; those at and to the right of the cursor are moved
to the left to fill the void.  The cursor is left in column 1.
.HI 10 control-z
Toggle case conversion mode.  The status of the case conversion
indicator is inverted; if case inversion was on, it is turned off,
and vice versa.
Case inversion, when in effect, causes all upper case letters to
be converted to lower case, and all lower case letters to be
converted to upper case.  Note, however, that 'se' continues
to recognize alphabetic line numbers in upper case only, in contrast
to the "case inversion" option (see the description of options above).
When case inversion is on, "CASE" appears in the
status line.
.HI 10 control-_
Insert newline.  A newline character is inserted before
the current cursor position, and the cursor is moved one position
to the right.  The newline is displayed according to the current
non-printing replacement character (see the "u" option).
.tc
.HI 10 control-\
Tab left and erase.
Characters are erased starting with the character at the nearest tab
stop to the left of the cursor up to but not including
the character under the cursor.  The rest of the line,
including the cursor, is moved to the left to close the gap.
.tc \
.HI 10 control-^
Tab right and erase.
Characters are erased starting with the character under the cursor
up to but not including the character at the nearest tab stop to
the right of the cursor.  The rest of the line is then
shifted to the left to close the gap.
.HI 10 NEWLINE
Kill right and terminate.  The characters at and to the
right of the current cursor position are deleted,
and the line is terminated.
.HI 10 DEL
Kill all.  The entire line is erased, along with any error
message that appears in the status line.
.HI 10 ESC
Escape.  The ESC key provides a means for entering 'se's
control characters literally as text into the file.  In fact,
any character that can be generated from the keyboard is
taken literally when it immediately follows the ESC key.
If the character is non-printing (as are all of 'se's control characters),
it appears on the screen as the current non-printing
replacement character (normally a blank).
.in -10
