.\"	$OpenBSD: mg.1,v 1.32 2007/05/31 19:20:13 jmc Exp $
.\"
.Dd $Mdocdate: July 4 2007 $
.Dt MG 1
.Os
.Sh NAME
.Nm mg
.Nd emacs-like text editor
.Sh SYNOPSIS
.Nm mg
.Op Ar options
.Op Ar file ...
.Sh DESCRIPTION
.Nm
is intended to be a small, fast, and portable editor for
people who can't (or don't want to) run the real emacs for one
reason or another, or are not familiar with the
.Xr vi 1
editor.
It is compatible with emacs because there shouldn't
be any reason to learn more editor types than emacs or
.Xr vi 1 .
.Pp
The options are as follows:
.Bl -tag -width Ds
.It Ar +number
Go to the line specified by number (do not insert
a space between the "+" sign and the number).
If a negative number is specified, the line number counts
backwards from the end of the file i.e. +-1 will be the last
line of the file, +-2 will be second last, and so on.
.It Fl f Ar <mode>
Run the mode command for all buffers created from
arguments on the command line, including the
scratch buffer and all files.
.It Fl n
Turn off backup file generation.
.El
.Sh KEY BINDINGS
Normal editing commands are very similar to Gnu Emacs.
In the following examples, ^X means control-X, and M-X means Meta-X,
where the Meta key may be either a special key on your keyboard
or the ALT key; otherwise ESC followed by the key X works as well.
.Pp
.Bl -tag -width xxxxx -compact
.It ^F
Forward character.
.It ^B
Backwards character.
.It ^N
Next line.
.It ^P
Previous line.
.It ^A
Start of line.
.It ^E
End of line.
.It ^D
Delete current character.
.It ^S
Interactive search forward.
.It ^R
Interactive search backwards.
.It M-%
Interactive search-and-replace.
.It ^O
Open a new line at cursor position.
.It ^T
Transpose characters.
.It ^U
Repeat next command 4 times
(can be cascaded i.e. ^U^U^F will move 16 characters forward).
.Pp
.It ^K
Kill to end of line (placing into kill buffer).
.It ^Y
Yank kill buffer into current location.
.It ^SPC
Set mark.
.It ^W
Kill region
(cuts from previously set mark to current location, into kill buffer).
.It M-W
Copy region (into kill buffer).
.Pp
.It ^V
Next page.
.It M-V
Previous page.
.It M-<
Start of buffer.
.It M->
End of buffer.
.Pp
.It ^X^C
Save buffers and quit.
.It ^X-O
Next window.
.It ^X-N
Next window.
.It ^X-P
Previous window.
.It ^X-U
Undo.
.It ^_
Undo.
.El
.Pp
For more key bindings, type
.Dq M-x describe-bindings .
.Sh CONFIGURATION AND COMMANDS
Amongst other major differences, the
.Nm
configuration files are much simpler than real emacs.
There are two configuration files,
.Pa .mg ,
and
.Pa .mg-TERM .
Here,
.Ev TERM
represents the name of your terminal type; e.g., if your terminal type
is set to
.Dq vt100 ,
.Nm
will use
.Pa .mg-vt100
as a startup file.
The terminal type startup file is used first.
The startup file format is a list of commands, one per line, as used for
interactive evaluation, e.g.:
.Bd -literal -offset indent
auto-fill-mode
set-fill-column 72
global-set-key "\e^x\e^f" find-file
.Ed
.Pp
Here's another example sequence that you may find useful.
By default,
.Dq ()
and
.Dq []
are recognized as brackets, so bracket matching can be done.
The following defines
.Dq {}
as brackets, and turns on the mode that causes
the cursor to "blink" to show you matching brackets.
.Bd -literal -offset indent
global-set-key } blink-matching-paren-hack
blink-matching-paren
set-default-mode blink
.Ed
.Pp
More complicated key mappings are also possible, though there are some
internal limitations compared to regular emacs.
An example of how to map control characters and sequences follows,
illustrating the Gosling-like line scrolling characters.
.Bd -literal -offset indent
global-set-key "\\^Z" scroll-one-line-up
global-set-key "\\ez" scroll-one-line-down
global-set-key "\\^_" suspend-emacs
.Ed
.Pp
In order to use 8-bit characters, the Meta key needs to be disabled.
This is required to read high bit characters like German umlauts.
ESC can be used instead of the Meta key \(en see the
.Sx KEY BINDINGS
section for details.
Execute the following command or add it to
.Pa .mg
to disable the Meta keys on startup:
.Bd -literal -offset indent
meta-key-mode
.Ed
.Sh FILES
.Bl -tag -width ~/.mg-TERM -compact
.It Pa ~/.mg
normal startup file
.It Pa ~/.mg-TERM
terminal-specific startup file
.El
.Sh SEE ALSO
.Xr vi 1
.Sh CAVEATS
.Nm
differs primarily in not having special modes for tasks other than
straight editing, e.g., mail and news, and in not having special modes that
support various programming languages.
It does have text justification
and auto-fill mode.
Since it is written completely in C, there is no
language in which you can write extensions.
However, you can rebind keys and change some parameters.
There are no limits to line length or format.
Command, buffer, and file name completion and listing can
be done using the spacebar and tab keys.