XVT(1)

NAME
xvt - VT100 emulator for the X window system

SYNOPSIS
xvt [ options ]

DESCRIPTION
Xvt is a VT100 terminal emulator for X. It is intended as a replacement for xterm(1) for users who do not require the more esoteric features of xterm. Specifically xvt does not implement the Tektronix 4014 emulation, session logging and toolkit style configurability. As a result, xvt uses much less swap space than xterm - a significant advantage on a machine serving many X sessions.

OPTIONS
The options supported by xvt (which, with the exception of -msg, are a subset of those supported by xterm) are listed below. Most command line arguments have X resource equivalents and these are listed in the following table.

-e command [ arguments ]
    Run the command with its command line arguments in the xvt window. If this option is used, it must be the last on the command line. If there is no -e option then the default is to run the program specified by the SHELL environment variable or, failing that, sh(1). This option also causes the window title and icon name to be set to the name of the program being executed if the are not overwritten by a more specific option.

-display display-name
    Attempt to open the xvt window on the named X display. In the absence if this option, the display specified by the DISPLAY environment variable is used.

-geometry window-geometry
    Create the window with the specified X window geometry.

-background color
    Use the specified color as the window's background color.

-bg color
    Same as -background.

-foreground color
    Use the specified colour as the window's foreground color.

-fg color
    Same as -foreground.

-cr color
    Set the color used for the text cursor.

-bw number
    Set the window border width to number pixels. Many window managers ignore existing window borders and construct their own and so, if you are using such a window manager, this option will be ignored.

-bd color
    Set the border color. As with border width, this option will usually be disregarded with respect to the window's outer border. It does, however, set the color of the line separating the scroll bar from the main part of the window.

-font fontname
    Set the main text font used by xvt.

-fn fontname
    Same as -font.

-fb fontname
    Set the font used for the vt100 bold rendition style. If this option is not set then xvt will render in bold by overprinting the normal font.

-name name
    Set the name that is used when looking up X resource values for this instance of xvt. This option also sets the icon name and window title unless they are set explicitly.

-title text
    Set the string that is displayed in the window's title bar if it has one.

-T text
    Same as -title

-n text
    Set the name that will be used to label the window's icon or displayed in an icon manager window. This option also sets the window's title unless it is set expicitely.

-sl number
    Set an upper bound for the number of lines that will be saved when they have scrolled off the top of the window.

-sb Start up with the scrollbar visible. The scrollbar can be displayed or hidden at any time simply by holding down the CONTROL key on the keyboard and pressing any mouse button. The visibility of the scrollbar does not determine whether scrolled text is saved or not - as with xterm, text scrolled off the top of the window is always saved up to the current maximum number of lines.

-rw Enable reverse wrapping of the cursor so that, for example, lines typed to a shell that are longer than the width of the screen can be edited. This is the same as the xterm reverse wrap option.

-cc string
    Input or modify the character classes that are used to determine what is a word when a double click is used to select a word of displayed text. This is identical to the same option in xterm - see the xterm manual page for a description of the syntax of string.

-iconic
    Start up with the window already iconized.

-msg
    Enable messages to the terminal window from programs like write(1). By default, xvt windows have messages disabled. Executing an xvt with the -msg option has the same effect as running it normally and then executing the command mesg y to enable messages.

-8  Treat characters as having eight bits - this is the default. When in eight bit mode, xvt displays eight bit characters and pressing a keyboard key with the Meta key held down generates the character code with the MSB set.

-7  Treat characters as having seven bits. In this mode, each character is stripped to seven bits before it is displayed and pressing a keybaord key with the Meta key held down causes the normal character to be preceded by the Escape character.

-ls Run a login shell. This option causes xvt to execute its shell with a name beginning with `-'. In the case of csh(1) this results in the .login and .logout files being interpreted at the start and end of the session.

-sf Enable Sun function key escape codes. The default is standard xterm compatible function codes.

-rv Run in reverse video - that is, exchange the foreground and background colors. This option has no effect if either the foreground or background color is set explicitly.

-C  Connect this terminal to the system console. This option is only implemented for SunOS 4 and for a user who has read and write access to /dev/console.

-console
    Same as -C.

X RESOURCES
Almost all the command line options have X resource counterparts and these are listed in the following table. Like xterm, xvt uses the class name XTerm and so resource options set for XTerm will work for both xterm and xvt windows.

Command line options and X resources
 | X resource
Command line | Instance | Class
-background or -bg | background | Background
-bd | borderColor | BorderColor
-bw | borderWidth | BorderWidth
-C or -console | - | -
-cc | charClass | CharClass
-cr | cursorColor | CursorColor
-display | - | -
-e | - | -
-fb | boldFont | BoldFont
-font or -fn | font | Font
-foreground or -fg | foreground | Foreground
-geometry | geometry | Geometry
-iconic | iconic | Iconic
-ls | loginShell | LoginShell
-msg | messages | Messages
-n | iconName | IconName
-name | - | -
-rv | reverseVideo | ReverseVideo
-rw | reverseWrap | ReverseWrap
-sb | scrollBar | ScrollBar
-sf | sunFunctionKeys | SunFunctionKeys
-sl | saveLines | SaveLines
-title or -T | title | Title
-8 (on) and -7 (off) | eightBitInput | EightBitInput

NAMES TITLES AND ICON NAMES
One occasionally confusing aspect of xvt and other X applications is the collection of names that an application window can have and the relationship between the names and the command line options used to set them. This section attempts to make the situation a bit clearer in the case of xvt.

In fact, each terminal window has three names, its resource name, its title and its icon name. These three names are distinct and have different functions, although they usually have the same value. The resource name is the command name used to identify X resource options in the resources database, The title is the text that is displayed in the title bar, if there is one, and the icon name is the name that appears in the window's icon or represents it in the icon manager window.

The rule about which option sets which name is that -name and -e set both the title and the icon name in addition to their main function and -n sets the title as well as the icon name. Conflicts are resolved by giving the options priorities which are, in increasing order, -e, -name, -n and -title. Hence, for example, -e only sets the title if none of the other options is used.

THE SCROLL BAR
Lines of text that scroll off the top of the xvt window are saved automatically (up to a preset maximum number) and can be viewed by scrolling them back into the window with the scrollbar. The scrollbar itself can be displayed or hidden by clicking any mouse button in the window while holding down the CONTROL key on the keyboard. When using the scrollbar, the left and right mouse buttons are used for scrolling by a few lines at a time and the middle button is used for continuous scrolling. To use the middle button, press it in the scroll bar and hold it down. the central shaded part of the scrollbar will then attach itself to the cursor and can be slid up or down to show different parts of the sequence of saved lines. When scrolling with the left and right buttons, the left button is used to scroll up and the right is used to scroll down. Assuming that there are enough hidden lines, the distance scrolled with either button is equal to the number of lines between the cursor and the top of the window. Hence, pressing the left cursor opposite a line of text will result in that line being moved to be the top of the window and pressing the right button will cause the top line to be moved down so that it is opposite the cursor.

TEXT SELECTION AND INSERTION
Xvt uses the same kind of text selection and insertion mechanism as xterm. Pressing and releasing the middle mouse button in an xvt window causes the current text selection to be inserted as if it had been typed on the keyboard. For the insertion to take place, both the button press and the button release need to be done with the cursor in the xvt window.

The left and right mouse buttons are used to select text, with the left button being used to start a selection and the right button being used to modify an existing selection. Any continuous block of displayed text can be selected. If both ends of the text block are visible in the window then the easiest way to select it is to position the cursor at one end and press the left mouse button, then drag the cursor to the other end with the button held down before releasing the button. If the block is larger than the window then you must first use the left mouse button to select one end, then use the scroll bar to scroll the other end into view and finally use the right mouse button to extend the selection. The effect of pressing the right mouse button is to move the nearest end of the current selection to the current cursor position.

The other way to make selections in xvt is to use double and triple clicks of the left mouse button with a double click selecting a word and a triple click selecting a whole line. For this purpose, a word is a sequence of characters in the same class. The default character classes are:

+   the upper and lower case letters, digits and '_' (underscore) all in one class;

+   the white space characters all in one class;

+   each of the remaining punctuation characters in a class by itself.

If you want to change the character classes so that, for example, you can select a UNIX pathname or a mail address in one double click, then you can do so by using the -cc command line option or the charClass X resource. Multiple clicking can be combined with dragging to select a sequence of consecutive words or lines.

Although xvt essentially mimics the behaviour of xterm in its support of text selection and insertion, there are a couple of minor differences:

+   xvt respects TAB characters in selected text and does not automatically convert them into spaces as does xterm;

+   xvt will let you abort a text insertion if you realise you have made a mistake before releasing the middle mouse button.

BUGS
Pasting very large quantities of text does not work.

AUTHOR
John Bovey, University of Kent, 1992 and 1993.