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 explicitly.
-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.