MUX(9.1) MUX(9.1) NAME mux, ismux, invert - layer multiplexer for jerq SYNOPSIS mux [ -l commands ] mux exit mux cd directory ismux [ - ] invert DESCRIPTION Mux manages asynchronous windows, or layers, on the jerq terminal. Upon invocation, it loads the jerq with a program (default /usr/jerq/lib/muxterm, 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 cursor indicates that an operation 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 indi- cated (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 Current and Top, which pulls a layer to the front of the screen and MUX(9.1) MUX(9.1) makes it the current layer for keyboard and mouse input. Non-current layers are indicated by a light border. There is a point in each layer, called the `Unix point', where the next character from Unix will be inserted. The Unix point advances whenever characters are received from Unix, but not when echoing typed characters. When a newline is typed after the Unix point, characters between the Unix point and the newline, inclusive, are sent to Unix and the Unix point advanced to after the newline. This means that shell prompts and other output will be inserted before char- acters that have been typed ahead. No other characters are sent to Unix (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 jim(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 jim'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 button 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. 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 the optional argument, no message is pro- duced. Invert reverses the sense of video, from black on white to white on black, or vice versa. 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 MUX(9.1) MUX(9.1) 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. FILES /usr/jerq/lib/muxterm terminal program /tmp/.mux* temporary file used by -l option SEE ALSO 32ld(9.1), jim(9.1), jx(9.1), term(9.1) 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).