ed.txt

PC x386 bios source code

Calling the editor
------------------

Call ED.COM using

        ED [-m=macfile] [file]

File is the (optional) name of the file to be edited. If this file is invalid
or doesn't exist yet, "Disk error" is indicated. If the -m=macfile option is
specified (macfile is the name of the keyboard macro file), the macro file is
read on startup.

On errors the editor expects you to hit the space bar as an acknowledgement.

Some control characters can modify video attributes (if the editor is installed
properly for your screen). Insert the chars using the ^P command:

^B	Boldface on
^U	Underline on
^N	Normal (bold and underline off)

Hard tabs are expanded. As usual, tab positions are at column 9, 17, 25 etc.
The end of the file is displayed by a gray area.

Editor commands
---------------

For many commands function keys can also be used.

^A      word left
^C      page down
^D      character right
^E      line up
^F      word right
^G      delete char right
^H      backspace, delete left
^I      tabulator (insert a hard tab)
^J      jump to symbol = search
        Enter word to be searched. The search is case-sensitive.
        Cursor jumps to first instance in text (search next: ^L)
^K      prefix for block, file and assembler commands
^L      repeat previous search (& replace)
^N      insert line break
^O      prefix for macro commands
^P      prefix for entering control chars
        (to enter ^_ type ^_^P^_<Enter>)
^Q      prefix for jump commands
^R      page up
^S      character left
^T      delete word right
^U      cursor line -> middle of the screen
^V      toggle insert / overwrite
^W      scroll up
^X      line down
^Y      delete line
^Z      scroll down
ESC     exit editor - also see file management.

Block operations
----------------

All block operations are line-oriented, i.e. they always treat entire lines.

^KA     block = all (entire text)
^KB     mark block beg
^KC     copy block
^KE     mark block end
^KJ	append (join) block to file (ignores ^Z)
^KK     mark block end
^KN     block = nothing
^KR     read block
^KV     move block
^KW     write block
^KY     delete block

Quick jump commands
-------------------

^QA     Search and replace. Asks for options. Valid options are:

	  g = global (start from beginning)
	  n = don't prompt for replacement
	  u = don't distinguish upper and lower case
	  w = search whole words only

	Valid answers to the prompt are:

	  y   = ok, do replace
	  n   = don't replace this one
	  *   = go ahead, don't ask me any more
	  Esc = stop it
		
^QB     jump to block beg
^QC     jump to text end
^QD     jump to line end
^QE     jump to block end
^QF	search (same options as ^QA)
^QI     toggle auto-indent option
^QK     jump to block end
^QL     undo changes in current line
^QR     jump to text beg
^QS     jump to line beg
^QY     delete to end of line
^QZ	delete to beg of line

File management
---------------

When calling ED from DOS a main file may be specified on the command line which
is then read into the text buffer.

Files are written back without query (there is a special command to throw away
changes made to the file). ED does not make .BAK files (the MS-DOS file system
is too damn slow).

The editor can quickly switch between two files: main and include. Both files
must fit into the text buffer (about 64 K) together.

Esc     Exit ED
        - from main: save main, return to DOS
        - from incl: save incl, return to main

^KI     Back to the previous include file (name displayed in status line)

^KL     Load/change include file
        - from main: load new include file
        - from incl: save incl, load new include file

^KM     Load/change main file
        - from main: save main, load new main file
        - from incl: save incl, back to main

^KQ     Throw away changes (query)
        - from main: don't save main, return to DOS
        - from incl: don't save incl, return to main

^KS     Save current file (manual save)

Should it be impossible to save a file the usual way (disk full etc.), mark the
text with ^KA, write it with ^KW to another disk and exit ED with ^KQ. If you
are prompted for a save filename, but want to throw away the file, enter 'nul'
as filename. DOS will dutifully write the file to the null device.

Function keys
-------------

Function keys can be used for some commands:

up      cursor up
down    cursor down
left    cursor left             ^left   word left
right   cursor right            ^right  word right
PgUp    page up                 ^PgUp   mark block beg
PgDn    page down               ^PgDn   mark block end
Home    jump to line beg        ^Home   jump to text beg
End     jump to line end        ^End    jump to text end

Ins     toggle insert/overwrite mode
Del     delete char right
^BS     delete to end of line

ScrLock Lock cursor line. The cursor will always remain in the same line of the
        screen (as far as possible). This is nice for bulk revisions. The
	cursor line can be moved with ^W, ^Z and ^U.

Keyboard Macros
---------------

The following keys can be programmed with macros of (nearly) any length (all
together up to 868 bytes, where each keystroke takes 1..2 bytes). Which keys
can be used may also depend on your keyboard driver.

                F1..F10
        Shift   F1..F10
        Ctrl    F1..F10
        Alt     F1..F10
        Alt     A..Z
        Alt     1..9,0,-,= (all keys in the number row)

^OL     Record keyboard macro

        Hit the destination key, then enter the command sequence (which is
        executed as usual, so you have visual feedback). Terminate the sequence
        with ^Break. Mistakes will also be recorded faithfully and cannot be
        edited except by recording the macro again.

        Macros can also be used during recording. Nesting is limited to
	15 levels, everything beyond is ignored. A macro that calls itself
        once will repeat 16 times, if it calls itself twice it will repeat
        2^16 times... Macros may be interrupted by ^Break.

^_      This suspends macro execution and lets the user enter data (no macros)
        terminated by <Enter>; macro execution will then resume. The user's
	<Enter> is ignored: The macro may edit or extend the entry (e.g. add a
	default extension to a filename).

^OW     Write macros to file

^OR     Read macros from file. This automatically executes the Alt-0 macro,
        making it possible to "chain" macros.

^OV     Update the display. Normally, the display is not updated during macro
	execution (resulting in fast execution of macros). This command can be
	used to show intermediate results.

Status line
-----------

The editor status is displayed in the top line of the screen:

        ^K  no   3  main + include filename

^K      Command prefix. Displayed while entering commands such as ^KB.

n       Indicates automatic indentation switched off. Toggle with ^QI.

o       Indicates overwrite mode. Toggle with ^V or INS.

3       Indicates cursor position in line.

Editing in the status line is similar to normal editing, but:

-       Trailing spaces are not cut off.
-       ^A jumps to beg of line
-       ^F jumps to end of line
-       Esc breaks the command.
-	When a default is given, if the first key pressed is a char,
	the default is cleared and the char is entered. If the first
	key is an editor command, the default can be edited. To insert
	something at the beginning of the default, first hit the
	cursor left key.