The xterm program is a terminal emulator for the X Window System. It provides DEC VT102 and Tektronix 4014 compatible terminals for programs that can't use the window system directly. If the underlying operating system supports terminal resizing capabilities (for example, the SIGWINCH signal in systems derived from 4.3bsd), xterm will use the facilities to notify programs running in the window whenever it is resized.
Cast of thousands...To give a bit of history, xterm predates X!
It was originally written as a stand-alone terminal emulator for the VS100 by Mark Vandevoorde, as my coop student the summer that X started.
Part way through the summer, it became clear that X was more useful than trying to do a stand alone program, so I had him retarget it to X. Part of why xterm's internals are so horrifying is that it was originally intended that a single process be able to drive multiple VS100 displays. Don't hold this against Mark; it isn't his fault.
I then did a lot of hacking on it, and merged several improved versions from others back in.
Notable improvements include the proper ANSI parser, that Bob McNamara did.
The Tek 4010 support came from a guy at Smithsonian Astrophysical Observatory whose name slips my mind at the moment.
Ported to X11 by Loretta Guarino.
Then hacked on at the X Consortium by uncounted people.
This FAQ is oriented toward the version of xterm distributed with XFree86 3.3, which is based on the X11R6.3 xterm, with the addition of ANSI color and VT220 controls.
Most of these configurations have X11R5 libraries. Only minor changes are needed to make xterm work on those systems. However, with X11R6 you can obtain better locale support, as well as new features such as the active icon.
Ftp: ftp://www.clark.net/pub/dickey/xterm/xterm.tar.gz
With X Consortium xterm, you have partial support for DEC VTxxx function keys. Function keys F1 to F12 correspond to DEC's F1 to F12 (sort of). Actually, DEC's VT220 terminals do not have codes for F1 through F5. They are reserved for local functions. And the VT220 (and up) terminals have 20 function keys. So you cannot do anything with the F13 through F20 (i.e., DO, HELP and SELECT). Finally, though xterm is reputed to be VT100-compatible, it has no support for the VT100 keypad (PF1 to PF4, and the "," key).
XFree86 xterm changes the X Consortium codes for F1 to F4 to match the VT100 PF1 to PF4, except when the emulation level is VT220 and up. In this case, it generates the same F1 to F4 codes as X Consortium xterm. Moreover, it adds a new resource sunKeyboard, which tells the program whether it has only 12 function keys (i.e., a Sun or PC keyboard). If so (this is selectable from the popup menu), you can use the control key with F1 to F12 to get F13 to F24, and use the "+" key on the keypad as an alias for "," (comma).
The emulation level for XFree86 xterm is set via the resource decTerminalID, e.g., to 220 for a VT220. Once set, applications can set the emulation level up or down within that limit. DEC's terminals are configured in much the same way by a setup option.
That is the simple way, using a couple of new resources. The traditional way to get function keys involves translations. I have seen a few postings on the newsgroups that do this. Here is one from Bruce Momjian <root@candle.pha.pa.us> for a VT220:
xterm $XTERMFLAGS +rw +sb +ls $@ -tm 'erase ^? intr ^c' \ -name vt220 -title vt220 -tn xterm-220 "$@" &
with the corresponding resources:
XTerm*VT100.Translations: #override \n\
<Key>Home: string(0x1b) string("[3~") \n \
<Key>End: string(0x1b) string("[4~") \n
vt220*VT100.Translations: #override \n\
~Shift <Key>F1: string(0x1b) string("OP") \n \
~Shift <Key>F2: string(0x1b) string("OQ") \n \
~Shift <Key>F3: string(0x1b) string("OR") \n \
~Shift <Key>F4: string(0x1b) string("OS") \n \
~Shift <Key>F5: string(0x1b) string("[16~") \n \
~Shift <Key>F6: string(0x1b) string("[17~") \n \
~Shift <Key>F7: string(0x1b) string("[18~") \n \
~Shift <Key>F8: string(0x1b) string("[19~") \n \
~Shift <Key>F9: string(0x1b) string("[20~") \n \
~Shift <Key>F10: string(0x1b) string("[21~") \n \
~Shift <Key>F11: string(0x1b) string("[28~") \n \
~Shift <Key>F12: string(0x1b) string("[29~") \n \
Shift <Key>F1: string(0x1b) string("[23~") \n \
Shift <Key>F2: string(0x1b) string("[24~") \n \
Shift <Key>F3: string(0x1b) string("[25~") \n \
Shift <Key>F4: string(0x1b) string("[26~") \n \
Shift <Key>F5: string(0x1b) string("[K~") \n \
Shift <Key>F6: string(0x1b) string("[31~") \n \
Shift <Key>F7: string(0x1b) string("[31~") \n \
Shift <Key>F8: string(0x1b) string("[32~") \n \
Shift <Key>F9: string(0x1b) string("[33~") \n \
Shift <Key>F10: string(0x1b) string("[34~") \n \
Shift <Key>F11: string(0x1b) string("[28~") \n \
Shift <Key>F12: string(0x1b) string("[29~") \n \
<Key>Print: string(0x1b) string("[32~") \n\
<Key>Cancel: string(0x1b) string("[33~") \n\
<Key>Pause: string(0x1b) string("[34~") \n\
<Key>Insert: string(0x1b) string("[2~") \n\
<Key>Delete: string(0x1b) string("[3~") \n\
<Key>Home: string(0x1b) string("[1~") \n\
<Key>End: string(0x1b) string("[4~") \n\
<Key>Prior: string(0x1b) string("[5~") \n\
<Key>Next: string(0x1b) string("[6~") \n\
<Key>BackSpace: string(0x7f) \n\
<Key>Num_Lock: string(0x1b) string("OP") \n\
<Key>KP_Divide: string(0x1b) string("Ol") \n\
<Key>KP_Multiply: string(0x1b) string("Om") \n\
<Key>KP_Subtract: string(0x1b) string("OS") \n\
<Key>KP_Add: string(0x1b) string("OM") \n\
<Key>KP_Enter: string(0x1b) string("OM") \n\
<Key>KP_Decimal: string(0x1b) string("On") \n\
<Key>KP_0: string(0x1b) string("Op") \n\
<Key>KP_1: string(0x1b) string("Oq") \n\
<Key>KP_2: string(0x1b) string("Or") \n\
<Key>KP_3: string(0x1b) string("Os") \n\
<Key>KP_4: string(0x1b) string("Ot") \n\
<Key>KP_5: string(0x1b) string("Ou") \n\
<Key>KP_6: string(0x1b) string("Ov") \n\
<Key>KP_7: string(0x1b) string("Ow") \n\
<Key>KP_8: string(0x1b) string("Ox") \n\
<Key>KP_9: string(0x1b) string("Oy") \n
! <Key>Up: string(0x1b) string("[A") \n\
! <Key>Down: string(0x1b) string("[B") \n\
! <Key>Right: string(0x1b) string("[C") \n\
! <Key>Left: string(0x1b) string("[D") \n\
*visualBell: true
*saveLines: 1000
*cursesemul: true
*scrollKey: true
*scrollBar: true
Note that real VT220 terminals use shifted function keys to mean something
different: the user-programmable keys (i.e., DECUDK). XFree86 xterm
supports this, but the translations do not (they're using shift to select
F13 to F20).
Here's another one, from Robert Ess <ress@spd.dsccc.com>:
#!/bin/sh
# vax
# 09-17-96 Bob Ess - initial creation
# 09-26-96 Shig Katada - Additional keybindings
#
# Script file to incorporate keybindings and command line
# options for connecting to a VAX node
# Usage statement
Usage(){
echo
echo " Usage : vax -options"
echo
echo " Options: -80 for 80 column terminal"
echo " -132 for 132 column terminal"
echo " -fg colorname"
echo " -bg colorname"
echo " -fn fontname"
echo " -fb bold fontname"
echo " -host [altair] [devel] [leonis] [castor]"
echo ""
echo " Example: \"vax -80 -fg white -bg black -fn 9x15 -fb 9x15b -host castor\""
echo " Starts a VAX session with an 80 column terminal"
echo " with a black background, white foreground, a normal"
echo " font of 9x15 and a bold font of 9x15b, and connects"
echo " to the node 'castor'"
echo
echo " If you need additional help, please call Workstation"
echo " Services at x92396."
echo
exit 1
}
# Default to a black foreground with a white background.
# Use the 9x15 and 9x15bold fonts. Connect to castor by default.
#
FG=black
BG=white
HOST=castor
FONT=9x15
BFONT=9x15bold
COLS=80
# Parse the command line arguments
#
while [ $# != 0 ];
do
case $1 in
-80) COLS=80
FONT=spc12x24c
BFONT=spc12x24b
shift
;;
-132) COLS=132
FONT=9x15
BFONT=9x15b
shift
;;
-fg) shift
FG=$1
shift;;
-bg) shift
BG=$1
shift;;
-fn) shift
FONT=$1
shift;;
-fb) shift
BFONT=$1
shift;;
-host) shift
HOST=$1
shift;;
-help) Usage;;
*) Usage;;
esac
done
xterm -title "VAX" -sb -sl 1200 -geo ${COLS}x24 -fg ${FG} -bg ${BG} \
-cr red -fn ${FONT} -fb ${BFONT} -xrm \
"XTerm*vt100.translations: #override \n\
<Key>Insert: string(\001) \n\
Shift <Key>Up: scroll-back(1,lines) \n\
Shift <Key>Down: scroll-forw(1,lines) \n\
Shift <Key>Right: string(0x1b) string("f") \n\
Shift <Key>Left: string(0x1b) string("b") \n\
Shift <Key>Delete: string(0x1b) string(0x08) \n\
Shift <Key>Tab: string(0x1b) string("*") \n\
<Key>0x1000FF0D: scroll-back(1,page) \n\
<Key>0x1000FF0E: scroll-forw(1,page) \n\
<Key>0x1000FF09: string(\010) \n\
<Key>0x1000FF0A: string(\005) \n\
<Key>BackSpace: string(0xff) \n\
<Key>Select: select-start() \n\
<Key>0x1000FF02: select-end(PRIMARY,CUT_BUFFER0) \n\
Meta <Key>0x1000FF02: select-end(CLIPBOARD) \n\
<Key>0x1000FF04: insert-selection(PRIMARY,CUT_BUFFER0) \n\
Meta <Key>0x1000FF04: insert-selection(CLIPBOARD) \n\
<Key>F1: string(0x1b) string("OP") \n\
<Key>F2: string(0x1b) string("OQ") \n\
<Key>F3: string(0x1b) string("OR") \n\
<Key>F4: string(0x1b) string("OS") \n\
<Key>F5: string(0x1b) string("OA") \n\
<Key>F11: string(0x1b) string("[23~") \n\
<Key>F12: string(0x1b) string("[24~") \n\
<Key>KP_0: string(0x1b) string("Op") \n\
<Key>KP_1: string(0x1b) string("Oq") \n\
<Key>KP_2: string(0x1b) string("Or") \n\
<Key>KP_3: string(0x1b) string("Os") \n\
<Key>KP_4: string(0x1b) string("Ot") \n\
<Key>KP_5: string(0x1b) string("Ou") \n\
<Key>KP_Divide: string(0x1b) string("OP") \n\
<Key>KP_Multiply: string(0x1b) string("[29~") \n\
<Key>KP_Enter: string(0x1b) string("OM") \n\
<Key>KP_Subtract: string(0x1b) string("Om") \n\
<Key>KP_Add: string(0x1b) string("Ol") \n\
<Key>KP_Decimal: string(0x1b) string("On") \n\
<Btn1Down>: select-start() \n\
<Btn1Motion>: select-extend() \n\
<Btn1Up>: select-end(PRIMARY,CUT_BUFFER0) \n\
Button1<Btn2Down>: select-end(CLIPBOARD) \n\
Button1<Btn2Up>: ignore()" \
-e telnet $HOST &
The usual context for this question is setting the title according to the current working directory. People post answers to this periodically on the newsgroups. Here is one that I have seen, from Roy Wright <nobody@roystoy.dseg.ti.com>. In your /etc/profile after:
if [ "$SHELL" = "/bin/pdksh" -o "$SHELL" = "/bin/ksh" ]; then PS1="! $ " elif [ "$SHELL" = "/bin/zsh" ]; then PS1="%m:%~%# " elif [ "$SHELL" = "/bin/ash" ]; then PS1="$ " else PS1='\u@\h:\w\$ ' fi
add:
if [ "$TERM" = "xterm" ]; then PS1="\033]2;\u@\h:\w\007bash$ " fi
The terminator "\007" is a problem area. Xterm historically uses this character, though it is non-ANSI. The "correct" character should be a "\233" string terminator, or "\033\\", which is the 7-bit equivalent. XFree86 xterm recognizes either (the "\007" or string terminator); waiting for the first of these.
You may have resource or environment problems that prevent you from setting the title at all. Newer xterms (starting somewhere in X11R5) use the $LANG variable. If your locale is incorrectly installed, you will be unable to set the xterm's title. As noted by Mikhail Teterin <mi@rtfm.ziplink.net>: Make sure that the locale (LANG and/or LOCALE environment variable) is known to X Window System. Check ${X11ROOT}/lib/X11/locale.* for it. If it is not listed in either one of the files, find the nearest match and add an alias to it. Restart X if you have made changes.
On a related note, some people want to know how to read the title from an xterm. This works for XFree86 xterm and dtterm, but not for other variations:
#!/bin/ksh
# Echo the current X term title bar to standard output.
# Written by Icarus Sparry <icarus@bath.ac.uk> 11 Apr 1997
#
exec </dev/tty
old=$(stty -g)
stty raw -echo min 0 time ${1-10}
print "\033[21t\c" > /dev/tty
IFS='' read -r a
stty $old
b=${a#???}
print -R "${b%??}"
But it is possible to avoid escape sequences altogether (from
Hemant Shah <shah@typhoon.xnet.com>):
$ xprop -id $WINDOWID | grep WM_NAME WM_NAME(STRING) = "this is my title" current_title=$(xprop -id $WINDOWID | grep WM_NAME | cut -d= -f2)
You may also have a problem with the terminfo description. As distributed, the X11R6 terminfo for xterm does not have the acsc string defined, so most implementations of curses do not try to use the alternate character set.
Finally, some people confuse the VT100 graphic characters with the VT220 support for DEC technical character set. These are distinct (7-bit) character sets. Xterm currently does not support this.
Check the terminal description, to see if it is installed properly, e.g., for ncurses, which uses terminfo.
Finally, some applications (that do not interface properly with terminfo or termcap) may need the environment variable $COLORTERM to be set.
stty -ashows the rows and/or columns values as 0, or some other value (such as 65) which has nothing to do with the actual window size.
You may be able to use the resize program to issue the ioctl's that will notify your application of the actual screen size. This does not always work for the reasons just mentioned. Newer versions of stty let you specify the screen size, though it will not be updated if you resize the xterm window:
stty rows 24 columns 80Most full-screen applications also check if the $LINES and $COLUMNS variables are set, using those values to override the terminal description:
setenv LINES 24 setenv COLUMNS 80Why 65 lines? The standard xterm terminfo description specifies 65 lines, perhaps because someone liked it that way. Real VT100's are 24 lines. I once used (and wrote applications for) a Bitgraph terminal, which emulated Vt100, but displayed 65 lines.
The libncurses.so.3.0 corresponds to ncurses 1.9.8a; while there have been interface changes to ncurses past this point (the current version of ncurses), the termcap interface should still be compatible. So (for xterm) it doesn't matter much which version of ncurses you have installed. However, other applications may not work properly. Some people have advised just linking libncurses.so.2.0 to libncurses.so.3.0, but that won't work well at all (one person simply linked libncurses.so.3.0 to the libtermcap.so, which may work...). A better solution would be to install the later version of ncurses, with a link (if you must) from the newer version to the older library.
Since there is little agreement on the set of shared libraries that are assumed to be present on the user's system, XFree86 distributes xterm statically linked against termcap because that is simplest, and because you lose functionality (the $TERMCAP variable) when linked against terminfo libraries such as ncurses.
A workaround is to copy /usr/X11R6/lib/X11/etc/xterm.termcap to /etc/termcap.
This is fixed another way in the most recent (XFree86 3.3.1) release. If xterm cannot find the terminal description, it will accept that, though it will print a warning. If xterm does not find the termcap entry, it will not set the $TERMCAP variable.
Perhaps your system does not have enough pty's, or (a recent problem reported with newer Linux kernels, especially RedHat) the major device numbers of the pty's may have changed during a kernel upgrade.
This may be due to incompatible terminal descriptions for xterm. With XFree86 3.2, I modified the terminal description for XFree86 xterm to use the VT220 (aka ISO 6429) controls that allow an application to turn off highlighting (or bold, underline) without modifying the other attributes. The X Consortium xterm does not recognize these controls.
If, for example, you are running an older xterm and rlogin to a system where the newer xterm has been installed, you will have this problem, because both programs default to $TERM set to xterm. The solution for mixed systems is to install the newer terminal description as as a different name (e.g., xterm-color) and set the termName resource accordingly in the app-defaults file for the system which has the newer xterm.
When I change font size often I will get the double-refresh, and when that happens the text program gets 2 resize events.. Running a quick test, I got this: Going to a bigger font, it got a 53x20 resize, then a 80x24 resize. Going to a smaller font, it got a 120x27 resize, then a 80x24 resize.
Earlier I made a mention of changing font size in rxvt (And xterm does it to) causing 2 resize events. Well I just happened to do it in fvwm (Instead of fvwm 95) and found it seems to be a 'feature' of fvwm95, not XFree86 as I'd initially assumed.
Using the XFree86 xterm-53 with the active icon feature on, I get some problems resizing where the xterm window shrinks as small as possible and won't stay at whatever size you set it thereafter.
Comment out the PixmapPath and IconPath from your .fvwmrc file to disable the fvwm icons and restart the WM. Start an xterm. Iconify xterm and maximize it again. Use resize button or corners to resize the xterm.
The xterm now shrinks to a tiny size and attempts to resize it result in it shrinking again.
I've tried this with fvwm 1.23 and fvwm 2.0.46 with the same results. Olvm, olvwm and twm all behave correctly so it may be a fvwm problem.
This is configurable.
For example (from Bjorn Helgaas <helgaas@dhc.net>) this procedure adds these capabilities to the "xterm" terminfo definition on HP-UX 10.20:
cp /usr/lib/terminfo/x/xterm /usr/lib/terminfo/x/xterm.orig untic xterm > /tmp/xterm.src echo " smcup=\E7\E[?47h, rmcup=\E[2J\E[?47l\E8," >> /tmp/xterm.src tic /tmp/xterm.srcHowever, xterms that are linked with termcap are more flexible in this area than those linked with terminfo libraries. The xterm program supports a resource titeInhibit which manipulates the $TERMCAP variable to accomplish this. It sets the $TERMCAP variable for the client with the ti and te capabilities suppressed. Systems that use terminfo cannot do this. If you are running terminfo with the alternate screen controls in the terminal description, then you can suppress the switching to the alternate screen by the titeInhibit, but not the associated cursor save/restore and clear-screen operations.
XFree86 3.9s xterm implements a different set of controls which addresses this (in addition to the older set of controls, for compatibility). The new set of controls implements the entire ti sequence (save cursor, switch to alternate screen, clear screen) and te (switch to normal screen, restore cursor) as two control sequences that can be disabled by titeInhibit.
A few applications (reportedly IRIX 5.x and 6.x vi incorrectly move the cursor before initializing cursor-addressing. This will cause the end-string to restore the cursor to its position when it was saved by the initialization string (typically at the upper left corner of the screen).
You are probably talking about the backarrow key (on my keyboard, at the upper right of the QWERTY block), or the key labeled delete. Since xterm is emulating a VT100/VT220, the backarrow key should generate a 127 (often displayed as ^?). You would use a control/H to obtain a backspace on a real VT220.
Tastes differ on Unix, people expect the backarrow key to generate a backspace (or not). As I understand it, at one point, XFree86 picked up the sense of the erase character during initialization, so that xterm would in effect use the same erase character as the console. The current scheme (X11R6) uses keyboard mapping tables that are independent of the environment.
XFree86 xterm provides a resource toggle backarrowKey (from VT320) that changes this key between the two styles (backspace or delete).
Here's a picture of the VT100 numeric keypad:
+-----+-----+-----+-----+ | PF1 | PF2 | PF3 | PF4 | +-----+-----+-----+-----+ | 7 | 8 | 9 | - | +-----+-----+-----+-----+ | 4 | 5 | 6 | , | +-----+-----+-----+-----+ | 1 | 2 | 3 | | +-----+-----+-----+ ENT + | 0 | . | | +-----+-----+-----+-----+and the similar Sun and PC keypads:
+-----+-----+-----+-----+ | NUM | / | * | - | +-----+-----+-----+-----+ | 7 | 8 | 9 | | +-----+-----+-----+ + + | 4 | 5 | 6 | | +-----+-----+-----+-----+ | 1 | 2 | 3 | | +-----+-----+-----+ ENT + | 0 | . | | +-----+-----+-----+-----+Working in X Windows, the NUM (NumLock) key has better uses than an alias for PF1 (and is sometimes reserved). I use the F1 through F4 on the keyboard to implement PF1 through PF4, alias the keypad "+" to "," and use the existing "-" key.
I test the keyboard (for VT52/VT100/VT220) using vttest. If you find (or think that you have found) a problem with the keyboard handling of xterm, please test it with vttest first.
XTerm*internalBorder: 10 XTerm*highlightSelection: true XTerm*VT100*colorBDMode: on XTerm*VT100*colorBD: blue XTerm*VT100*colorULMode: on XTerm*VT100*colorUL: magenta XTerm.VT100.eightBitInput: true XTerm.VT100.eightBitOutput: true XTerm*scrollBar: true XTerm.VT100.titeInhibit: true XTerm.VT100*colorMode: on XTerm.VT100*dynamicColors: on ! Uncomment this to use color for underline attribute XTerm.VT100*colorULMode: on XTerm.VT100*underLine: off ! Uncomment this to use color for the bold attribute XTerm.VT100*colorBDMode: on XTerm.VT100*color0: black XTerm.VT100*color1: red3 XTerm.VT100*color2: green3 XTerm.VT100*color3: yellow3 XTerm.VT100*color4: blue3 XTerm.VT100*color5: magenta3 XTerm.VT100*color6: cyan3 XTerm.VT100*color7: gray90 XTerm.VT100*color8: gray30 XTerm.VT100*color9: red XTerm.VT100*color10: green XTerm.VT100*color11: yellow XTerm.VT100*color12: blue XTerm.VT100*color13: magenta XTerm.VT100*color14: cyan XTerm.VT100*color15: white XTerm.VT100*colorUL: yellow XTerm.VT100*colorBD: white XTerm.VT100*cursorColor: lime greenI have seen people say that the following resource is needed, but do not agree, since it is not used in xterm (perhaps in a window manager):
*customization: -color
You have specified the geometry for xterm too high in the hierarchy, and that 24x80 (or whatever the -geometry parameter happens to be) is applying to the menus in pixels. This resource makes the geometry apply to the menus as well as the VT100 widget:
XTerm*geometry: 80x24while this applies only to the VT100 widget:
XTerm.VT100*geometry: 80x24
These are the known bugs (or limitations) in the XFree86 3.3 xterm. They are also present in the other versions based on the X Consortium sources (color_xterm, ansi_xterm, kterm).
Note that of the emulators that support color, most do not support bce (back color erase). The bce capability is also called the "new color model", though it has been implemented in the IBM PC for quite a while.
xmkmf makeI have written a simple configure script for xterm which uses imake (or xmkmf) to generate a Makefile from the Makefile.in. I plan to restructure xterm to eliminate the hardcoded #ifdef's, replacing them with definitions that can be derived with the configuration script. The configure script is more flexible than xmkmf, since it allows you to enable or disable a variety of features. Type
configure --helpto get a list of options.
Though I plan to replace the hardcoded ifdef's with autoconfigured values, it will still continue to build properly with the imake environment, since that is how large distributions incorporate xterm.
I have implemented (like kermit) the spacing for double size characters. However, for completeness, xterm should display the scaled characters.
Done, except for the corresponding support in the VT52 emulation. It would be nice to have a dialog to control this.
My configure script currently provides tests for the variations of Athena widgets (Xaw3D, neXtaw). I intend to make additional changes to support Motif scrollbars and menus.
Just for completeness (though no one seems to want this feature).