MUX(9.1) MUX(9.1)
NAME
mux, ismux, invert - layer multiplexer for 5620
SYNOPSIS
mux [ -l command ... ]
mux exit
mux cd directory
ismux [ - ]
invert
DESCRIPTION
Mux manages asynchronous windows, or layers. Upon invoca-
tion, it loads the terminal with a program (default settable
by the environment variable MUXTERM) that is the primary
user interface. Option -l also creates a layer and invokes
the shell to run commands in it. (See windows(9.1)).
The command `mux exit' leaves mux, destroying all layers;
`mux cd' changes the directory of mux, and hence of layers
later created, but not of the current layers.
Each layer is essentially a separate terminal. Characters
typed into the layer are sent to the standard input of a
Unix process bound to the layer, and characters written on
the standard output of that process appear in the layer.
When a layer is created, a separate shell (the value of the
SHELL environment variable, or sh by default) is estab-
lished, and bound to the layer.
Layers are created, deleted, and rearranged using the mouse.
Depressing mouse button 3 activates a menu of layer opera-
tions. Releasing button 3 then selects an operation. At
this point, a gunsight or box cursor indicates that an oper-
ation is pending. Hitting button 3 again activates the
operation on the layer pointed to by the cursor.
The New operation, to create a layer, requires a rectangle
to be swept out, across any diagonal, while button 3 is
depressed. A box outline cursor indicates that a rectangle
is to be created. The Reshape operation, to change the size
and location of a layer on the screen, requires first that a
layer be indicated (gunsight cursor) and a new rectangle be
swept out (box cursor). The other operations are self-
explanatory.
In a non-current layer, button 1 is a shorthand for Top and
MUX(9.1) MUX(9.1)
Current, which pulls a layer to the front of the screen and
makes it the active layer for keyboard and mouse input. Th
current layer is indicated by a heavy border.
There is a point in each layer, called the `Unix point',
where the next character from the host Unix system will be
inserted. The Unix point advances whenever characters are
received from the host, but not when echoing typed charac-
ters. When a newline is typed after the Unix point, charac-
ters between the Unix point and the newline, inclusive, are
sent to the host and the Unix point advanced to after the
newline. This means that shell prompts and other output
will be inserted before characters that have been typed
ahead. No other characters are sent to the host (but see
the discussion of raw mode below). Therefore partially
typed lines or text anywhere before the Unix point may be
edited.
The default terminal program allows any text on the screen
to be edited, much as in sam(9.1). Text may be selected by
sweeping it with button 1 depressed. Typed characters
replace selected text.
All layers share a common `snarf buffer' (distinct from
sam's). The cut operation on button 2 deletes selected text
and puts it in the buffer; snarf copies selected text to the
buffer; paste replaces selected text (which may be null)
from the buffer; and send copies the snarf buffer to after
the Unix point.
Normally the terminal doesn't scroll as text is received,
but a button 2 menu item selects scrolling.
A scroll bar indicates what portion of all the text stored
for a layer is on the screen. (It measures characters, not
lines.) Releasing button 1 in the scroll bar brings the
line at the top of the screen to the cursor; releasing but-
ton 3 takes the line at the cursor to the top of the screen.
Button 2, treating the scroll bar as a ruler, brings the
indicated point in the whole stored text to the top of the
screen. Slide the cursor off either end of the scroll bar
with button 2 depressed to get right to an end of the file.
The NUM LOCK key advances a half page.
Ismux reports on its standard error whether its standard
output is a mux layer, and also generates the appropriate
exit status. With option `-', no message is produced.
Invert reverses the sense of video, from black on white to
white on black, or vice versa.
MUX(9.1) MUX(9.1)
Independent user-level programs can be loaded into layers,
see 32ld(9.1). SHIFT-SETUP freezes mux and complements the
video of the layer of the running user-level terminal pro-
cess. Hitting button 2 in this state will attempt to kill
the process; 1 or 3 will leave it running.
In raw mode or no-echo mode (see ttyld(4)) the Unix point
advances with each character typed after it. In 8bit mode,
characters with octal codes 0200 and greater print according
to the ISO Latin1 alphabet; see ascii(6).
FILES
temporary file used by -l option
SEE ALSO
32ld(9.1), sam(9.1), jx(9.1), term(9.1), windows(9.1)
R. Pike, `Blit Download Protocols', this manual, Vol. 2
DIAGNOSTICS
Mux refuses to create a layer when there is not enough mem-
ory. Space can be recovered by deleting a layer.
Error messages from mux are written directly to the layer
which caused them. They are usually meaningful only to sys-
tem administrators, and indicate system difficulties.
BUGS
Reshape only works properly for processes that arrange to
see if they have been reshaped, although most programs make
this arrangement.
The behavior of raw mode prohibits editing partially typed
lines when running cu(1).