The X Window User HOWTOv3.1 10 October 2002HalBurgisshal@foobox.netv3.12002-10-10hb Some minor additions and updates.
v3.02002-03-06hb Rewrite of the original document. Convert to DocBook. Many, many changes.
XX11XFreeXFree86X WindowGUIwindowsdesktopdisplaydisplay managerxdm
v4.x changes:
- artheader tag changed to articleinfo
- graphic tag is being depricated in DocBook 5.x. To prepare for
this, you should instead use the mediaobject tag.
- file format for imagedata has to be in capital letters.
- added support for PNG (notation in the DTD)
--s+ [ser@metalab.unc.edu]
aspell -H -c ~/ldp/x-user/LDP/howto/docbook/XWindow-User-HOWTO.sgml
submit@linuxdoc.org
export CVSROOT=:pserver:hal@cvs.linuxdoc.org:/cvsroot
cvs -d $CVSROOT login
pword: XXXXXXXXXXXXXX
$cvs get LDP/howto/docbook/XWindow-User-HOWTO.sgml
upload...
$ cvs commit XWindow-User-HOWTO.sgml !!!!!!!!!!!!!!!!
(from the LDP/howto/docbook/ dir)
check here: http://cvs.pld.org.pl/LDP/howto/docbook/XWindow-User-HOWTO.sgml
====================================
Start 3.1:
TODO:
Changes:
http://www.plig.org/xwinman (plus freshmeat)
VNC vs X for performance on network.
lbxproxy, performance.
Add fluxbox.
Start rewrite 01/13/02 Hal Burgiss.
Changes:
Converted to DocBook
Rewrite! Rewrite!
A zillion changes.
ToDo:
$DISPLAY
http://www.superant.com/cgi-bin/smalllinux.pl?smallX
http://www.linuxgazette.com/issue27/kaszeta.html (xdm)
http://linux.daphnis.com/RedHat/Custom-X-Tips.html#toc4 (Xclients, etc)
http://www.linuxjournal.com/print.php?sid=5304 (X config, etc)
log file
http://www.linux.gr/cgi-bin/man2html/usr/X11R6/man/man7/X.7.gz
http://www.x-docs.org/
startx entent log
_X11TransSocketUNIXConnect: Can't connect: errno = 111 giving up.
xinit: Connection refused (errno 111): unable to connect to X server
xinit: No such process (errno 3): Server error.
## Makefile to build this doc as HTML and TXT ####################
# X Windows User HOWTO Makefile
#
# Hal Burgiss hal@foobox.net
#
TITLE = XWindow-User-HOWTO
EXT = sgml
SRC_DIR = LDP/howto/docbook
HTML_DIR = X-USER
SRC = $(SRC_DIR)/$(TITLE).$(EXT)
BUILD = jade -t sgml -ihtml -d /usr/lib/sgml/stylesheets/ldp.dsl\#html
BUILD_TXT = jade -t sgml -i html -d /usr/lib/sgml/stylesheets/ldp.dsl\#html -V nochunks
SPELL_CMD = aspell -H -c
LINKS_CMD = /usr/bin/linkchecker *html
EDIT_CMD = /usr/bin/vim -g
TBROWSER = w3m
TMP_TXT = __tmp.sgml
WWW=/var/www/html/ldp/x-user
SRC_URL = http://feenix.burgiss.net/ldp/x-user/$(TITLE).$(EXT).gz
all: doc txt
doc: html
html:
rm -fr $(HTML_DIR)
mkdir -p __tmp_htmls
mv -f *.html __tmp_htmls 2ent/dev/null || :
mkdir -p $(HTML_DIR)
$(BUILD) $(SRC) ||\
(rm -f *.html entent mv -f __tmp_htmls/* . || : entent rm -rf __tmp_htmls entent false)
mv -f *html $(HTML_DIR)
mv -f __tmp_htmls/* . 2ent/dev/null || :
rm -fr __tmp_htmls
clean:
rm -fr $(HTML_DIR) *~ __tmp_htmls
edit:
$(EDIT_CMD) $(SRC)
spell:
$(SPELL_CMD) $(SRC)
spellchecker: spell
links:
cd $(HTML_DIR) entent $(LINKS_CMD)
linkchecker: links
linkcheck: links
txt:
$(BUILD_TXT) $(SRC) ent $(TMP_TXT).html
$(TBROWSER) -dump $(TMP_TXT).html ent $(TITLE).txt entent gzip -f $(TITLE).txt entent rm -f $(TMP_TXT).html
text: txt
www:
cp -fv $(HTML_DIR)/* $(TITLE).txt.gz $(SRC) $(WWW)
gzip -f $(WWW)/$(TITLE).sgml
rsync -auv $(WWW)/* feenix://$(WWW)/
submit:
@echo "Updated and ready: $(SRC_URL)" |\
mail -s "$(TITLE) update" submit@linuxdoc.org entent\
echo " $(TITLE) Submitted!"
This document provides basic information on understanding and configuring the
X Window System for Linux users. This is meant to be an introductory
level document. A basic knowledge of software configuration is assumed, as is
the presence of an installed and working X Window System.
Introduction The X Window System is an advanced, graphical
computing and network environment that was designed from the ground up as a
multi-user system. X was first released in 1984.
If you are not familiar with the basic concepts surrounding
X and it's related components, you should first
read the X Window System Architecture Overview HOWTO, http://linuxdoc.org/HOWTO/XWindow-Overview-HOWTO/index.html,
to get an idea of how the various pieces fit together. There is also
an attempt to define to various X related
terminology in the Appendix, if concepts such
as displays and X clients in this context are
confusing to you.
This document will address basic X Window configuration and usage on Linux. We will
also look at how X is commonly started in Linux,
and how the start up can be configured, and related issues. We will
not examine Window Manager (e.g.
fvwm), or Desktop Environment
(KDE and GNOME)
configuration. There are just too many variables there, and the pace of
change moves too quickly. Of course, to a large extent the user interacts
more directly with these components than the X server itself, so additional
reading would be worthwhile. Check your locally installed documentation, and
the respective home pages for more information.
Some other important points to remember here:
X is a client-server, multi-user system in
every respect, and not just a GUI.
X is not integrated into the operating system,
and rides on top of it, like other servers.
X is an open standard, and runs on many platforms.
What you actually see on the screen is the result of various components,
all working together: operating system, X,
Window Manager, and optionally, a desktop environment like
GNOME or KDE. These
are all plug and play components, meaning you can
interchange an individual component without touching the other components.
Each of the various components has its own configuration. This makes for a
very flexible, and potentially very robust, system. It also adds
complexity.
The discussion here will be limited to X as
implemented by The XFree86 Project,
Inc. on Linux. There are other implementations, including
commercial ones. XFree86 v4.x has been out for some time now, so we will be
assuming that version. Much of the discussion applies to the previous 3.x
version as well, but there are some occasional differences.
It is also worth noting that there are conceivably many ways to start
X, and to set up a Linux system. We will focus on
the common methods found in Linux distributions. Also, vendors may vary on
where they put configuration files, and how they name them. Keep this in mind
if you see such discrepancies in this document. If this is a problem, your
vendor surely has their own documentation. And as always, hopefully the man
pages will conform to your installation.
Also, we will look at various configuration files in the following sections.
These are all plain text files, and can be edited with your favorite editor.
Always make a backup copy before editing important files, in case Murphy pays
a visit (e.g. cp /etc/X11/XF86Config-4 /etc/X11/XF86Config-4.bak).
New Versions and ChangeLog The current official version of this HOWTO may be found at the Linux Documentation Project, http://www.linuxdoc.org/HOWTO/XWindow-User-HOWTO.html.
Pre-release versions may be periodically posted to http://feenix.burgiss.net/ldp/x-user/. v3.1: This is just some small, minor updates. Include link
to http://www.plig.org/xwinman/
as a good resource for shopping Window Managers. Add link for fluxbox,
a Window Manager with Tabbed windows. And add a brief section on improving
network performance. Verify links all work. v3.0: This is a major rewrite with several new sections. Some
sections were removed, with the focus more now on just
X itself (and not clients like Window Managers).
New maintainer too :-) v2.0: includes corrections from Guus Bosch, Brian J.
Miller, and myself, as well as lots of new updates and info. v1.4: include corrections and additions from Anthony J., and
some very good security tips from Tomasz Motylewski.To Do A rudimentary troubleshooting section. Probably for v3.2.
Feedback If you have questions or comments about this document, please feel free to
email me, Hal Burgiss at hal@foobox.net. I welcome any
suggestions, corrections, or additions. If you have information you would
like to see in future revisions, or you would like to contribute to a future
revision, please drop me a note.
Help! I have assumed maintainership of this document because it was abandoned, and
I had wanted to offer a suggested change. Well, to make a long story short,
this led to a major re-write. You can help make this a better document by
correcting inaccuracies, clarifying the unclear, and suggesting improvements.
There is much about this topic I may not know, or not have explained well. Your
help will improve this document and help other users. This document
needs your help!
Acknowledgments Thanks to the XFree86 development team for their efforts in providing a
robust and flexible GUI. And to the whole GNU/Linux and Open Source
community for making it all possible.
Also, the original author, Ray Brigleb.
Various users on comp.os.linux.x that have helped in one way or another,
whether they know it or not.
Lastly, http://google.com/linux,
who saved me much time with their incredible repository of information. Use
it to answer questions not answered here!
Copyright Copyright ent 2002, Hal Burgiss. Unless otherwise stated, Linux HOWTO documents are copyrighted by their
respective authors. Linux HOWTO documents may be reproduced and distributed
in whole or in part, in any medium physical or electronic, as long as this
copyright notice is retained on all copies. Commercial redistribution is
allowed and encouraged; however, the author would like to be notified of any
such distributions. All translations, derivative works, or aggregate works incorporating any
Linux HOWTO documents must be covered under this copyright notice. That is,
you may not produce a derivative work from a HOWTO and impose additional
restrictions on its distribution. Exceptions to these rules may be granted
under certain conditions; please contact the Linux HOWTO coordinator for more
information.
In short, we wish to promote dissemination of this information through as
many channels as possible. However, we do wish to retain copyright on the
HOWTO documents, and would very much like to be notified of any plans to
redistribute the HOWTOs, this one in particular! Some of the terms mentioned in this document are trade names. Unless
otherwise stated, all trademarks are property of their respective owners.X Window System is a trademark of the X Consortium, Inc
[now the OpenGroup?].
XFree86 is a trademark of The
XFree86 Project, Inc.
Linux is a Registered Trademark of Linus Torvalds.Standard Disclaimer The information and examples given here are for illustrative purposes. Use at
your own risk. Every attempt has been made to insure that the content of this
document was accurate when written. If you find inaccuracies, please send me
clarifications.
References to any particular company, product or brand name should not be
construed as an endorsement.
XFree86 Virtually every Linux distribution comes with XFree86's
X Window System implementation. This project, of
course, provides us the X server, but also includes an extensive suite of
utilities and applications to help implement a fully functional GUI
environment.
In fact, the list would be just too long to list everything that
comes with XFree86. In addition to the X server itself, here are a few of the
noteworthy utilities:xdm - the X Display Manager.
xfs - the X Font Server.
twm - a lightweight Window Manager.
xterm - the best known terminal emulator. Also,
xterm3d and nxterm.
xwd - a screen and window image capturer.
xf86config - X server configuration utility.
xdpyinfo - X display information utility. This
shows great detail about the X server.
xlsclients - lists currently connected X server
clients.
xlsfonts - lists fonts available to
X.
appres - lists the X resources that a
program will use.
xfontsel - an application for viewing or
selecting fonts.
xprop - a tool for displaying window
properties, such as the Class name of the client.
xset - sets user preferences for many things,
including mouse, keyboard, sound (bell), etc.
xsetroot - a program for changing the
root window appearance, e.g. setting a background color.
xvidtune - an application to adjust X server
video modes and monitor related settings.
xwininfo - displays information about a selected
window.
xmodmap - a utility for manipulating keyboard and mouse
button mappings.
Many, many fonts. And quite a bit of documentation as well.
There are many more. We'll just touch on a few of these utilities here. But
feel free to explore the others. Most should have their own man pages.
Hardware The X server controls both input (keyboard, mouse, etc) and output (display,
monitor) devices.
Compatible hardware is a tough topic, since it is very much a moving target.
We are forced here to avoid specifics, since this would surely change by the
time you read this. And would be tediously lengthy anyway.
So let's settle for some generalities. Most PC type
hardware is supported to one degree or another. Big help ;-)
Rule of thumb: if it is a device that uses a long-standing, commonplace
protocol (e.g. PS/2), it should be well supported. Conversely, if it is
something relatively new, with ground-breaking technology, the odds
are not as good. This is just the nature of the beast with open source
development versus manufacturers that cater more to the most popular
platforms. Some manufacturers are more co-operative than others too.
Now, some general guidelines:
Monitors - This is easy. Linux does not really need to be compatible with
the monitor per se. That is the job of the video card. Any monitor that
your graphics card can drive should do fine. Including, flat panel
monitors.
Video cards - This is much tougher. The X server is determined by the
the chipset. Many, many are supported. But inevitably there are always
some newer cards, or even revised cards, that are not. And some may have
better support and better optimization than others. Advanced
features such as multi-headed displays, 3D, TV out, DRI, etc., have some
support as well, though this should be researched first, as the support
may be limited. Supported cards are listed: http://xfree86.org/cardlist.html.
Open source drivers are often developed incrementally. For instance, a
particular card may work well for basic display purposes, but specialized
features such as 3D may come much later in the development cycle. This
is a quite different development model than with proprietary drivers from
the manufacturer.
Keyboards -- Any standard PC type keyboard should do fine,
including PS/2, USB and many infra-red devices. Probably many
non-standard ones too ;-)
Mice and other pointer devices -- Most should be supported including
PS/2, bus, serial, USB and many infra-red devices. Optical mice also. Unix
has long preferred three button mice, though more buttons is supported as
well. Many wheeled mice have X server support via the
IMPS/2 (IntelliMouse), or other specific protocols, though
may require supplemental configuration for some individual applications.
(See the Links section.)
Laptops have their own unique set of problems since the hardware tends to
be very specialized, and often different from what is commonly found on
desktop style systems. X is supported by many.
Check for details at http://www.linux-laptop.net/.
You can check the hardware compatibility list at your
distribution's web site too. This should give a very good idea of what
should work with your release.
Newer versions of XFree86 obviously will have better hardware support. If you
are using an older Linux version and don't have full hardware support, see
about upgrading XFree86. Check first to see if your distribution has updates
for your release.
XF86Config The primary configuration file for XFree86 is
XF86Config, which may exist on your system as
XF86Config-4 for XFree86 v4.x, or possibly other
variations (see man page). It is typically located as
/etc/X11/XF86Config, though again, there may be
variations in the path. If both a XF86Config-4
and XF86Config exist, XFree86 v4.x will use the former.
This is a required file.
XF86Config file defines hardware devices, and other
critical components of the X server environment.
While this is a plain text file, and is editable, it is most often created
during installation by whatever utility your vendor uses for this purpose.
XFree86 also includes the xf86config utility for this,
but many distributions have their own such utilities. These utilities can be
run after installation if need be, to alter the configuration, or if new
hardware is installed. Read your locally installed documentation first. If
you attempt to hand edit this file, be sure to make a backup copy first since
X won't start if this file is not to its liking
;-)
This file contains various sections. Each section defines some
fundamental aspect of XFree86, such as InputDevice (mouse,
keyboard, joystick, etc), monitor, or screen. The
XF86Config man page describes the sections and
common values for each. Note that the values listed in the man page is not a
comprehensive listing. There are many device specific options.
Check http://xfree86.org for notes
and tips on your hardware.
The author's current XF86Config-4, as generated by Red
Hat's installer for XFree86 4.1:
Section "ServerLayout"
Identifier "XFree86 Configured"
Screen 0 "Screen0" 0 0
InputDevice "Mouse0" "CorePointer"
InputDevice "Keyboard0" "CoreKeyboard"
EndSection
Section "Files"
# The location of the RGB database.
RgbPath "/usr/X11R6/lib/X11/rgb"
# Multiple FontPath entries are allowed (they are concatenated together)
# By default, Red Hat 6.0 and later now use a font server independent of
# the X server to render fonts.
FontPath "unix/:7100"
EndSection
# Module loading section
Section "Module"
Load "dbe" # Double-buffering
Load "GLcore" # OpenGL support
Load "dri" # Direct rendering infrastructure
Load "glx" # OpenGL X protocol interface
Load "extmod" # Misc. required extensions
Load "v4l" # Video4Linux
# Load "fbdevhw"
Load "pex5"
Load "record"
Load "xie"
EndSection
Section "InputDevice"
Identifier "Keyboard0"
Driver "keyboard"
Option "XkbLayout" "us"
# Option "AutoRepeat" "500 5"
# when using XQUEUE, comment out the above line, and uncomment the
# following line
# Option "Protocol" "Xqueue"
# Specify which keyboard LEDs can be user-controlled (eg, with xset(1))
# Option "Xleds" "1 2 3"
# To disable the XKEYBOARD extension, uncomment XkbDisable.
# Option "XkbDisable"
# To customize the XKB settings to suit your keyboard, modify the
# lines below (which are the defaults). For example, for a non-U.S.
# keyboard, you will probably want to use:
# Option "XkbModel" "pc102"
# If you have a US Microsoft Natural keyboard, you can use:
# Option "XkbModel" "microsoft"
EndSection
Section "InputDevice"
Identifier "Mouse0"
Driver "mouse"
Option "Device" "/dev/mouse"
Option "Protocol" "IMPS/2"
Option "Emulate3Buttons" "off"
Option "ZAxisMapping" "4 5"
EndSection
Section "Monitor"
Identifier "Sylvania F74"
VendorName "Unknown"
ModelName "Unknown"
HorizSync 30 - 70
VertRefresh 55 - 120
Option "dpms"
# Modelines go here if necessary. Use xvidtune to get proper values.
EndSection
Section "Device"
Identifier "ATI Rage 128"
Driver "r128"
BoardName "Unknown"
EndSection
Section "Device"
Identifier "Linux Frame Buffer"
Driver "fbdev"
BoardName "Unknown"
EndSection
Section "Screen"
Identifier "Screen0"
Device "ATI Rage 128"
Monitor "Sylvania F74"
DefaultDepth 24
Subsection "Display"
Depth 24
Modes "1400x1050" "1280x1024" "1152x864" "1024x768" "800x600"
EndSubSection
Subsection "Display"
Depth 16
Modes "1600x1200" "1400x1050" "1280x1024" "1152x864" "1024x768" "800x600"
EndSubSection
Subsection "Display"
Depth 8
Modes "1024x768" "800x600" "640x480"
EndSubSection
EndSection
Section "DRI"
Mode 0666
EndSection
Yours may look quite different. This is just one possible configuration with
gratuitous comments from Red Hat (and me), and is for a fairly ordinary set
up. There is nothing exotic here like multiple screens or displays.
It is beyond the scope of this document to explain this in detail. See the
XF86Config man page. Also, consider visiting
xfree86.org
and look for specific options that might apply to your card or other
hardware.
Just one quick note on the Screen section above. Notice there are
three sub-sections, identified as Display. Each sub-section
has a different Depth specified, (a.k.a. ColorDepth). The
Modes also vary somewhat according to the respective
Depth setting. The active Display sub-section
that will be used, is determined by the DefaultDepth setting
(unless over-ridden by command line options). The default in this example is
defined as 24, so the first sub-section will be used. Also,
the highest Mode listed in this sub-section will be the default
mode (resolution), which here is the first one listed. The first listed mode
also determines the viewable screen area, which can be smaller than the mode
(resolution) itself. In which case, you would have a virtual desktop that is
larger than the viewable screen. To have the viewable screen, and resolution
match, have the largest value as the first value listed for each
Mode.
Another note on the Modes here: what you see is the result of
my choices during Red Hat's Xconfigurator's configuration. These
are standard resolutions, but do not have to be! This is only limited by what
your hardware can support. And you don't have to use standard width x height
ratios either. Something like 1355x1112 is a valid setting (if
your hardware supports it and it floats your boat!).
The X server will reject any Modes it thinks are invalid. You
can cycle through valid modes to change screen resolution with
Ctrl-Alt-+ and Ctrl-Alt-- (that's the
keypad plus and minus keys).
In versions prior to v4.x, you would also see many Modeline
statements that attempted to define the monitor's capabilities. These
statements would look something like:
# 1024x768 @ 100Hz, 80.21 kHz hsync
Modeline "1024x768" 115.5 1024 1056 1248 1440 768 771 781 802 -HSync -VSync
Explicit Modeline definitions are not required as of 4.x ;-)
This sometimes required hand editing to get optimal values in earlier versions of
XFree86, though is generally not necessary with v4.x. The XFree86 Video
Timings HOWTO, http://www.linuxdoc.org/HOWTO/XFree86-Video-Timings-HOWTO/index.html
has a nice, but rather technical, explanation of this.
If whatever configuration utility you are using, does not automatically
recognize your video card or monitor specifications correctly, you are
unlikely to get an optimal configuration. In such cases, you may have to
manually supply the correct values. This should be available from your
owner's manual (you kept that, right?). Or, check the manufacturer's web site.
Again, hand editing of this file is generally unnecessary. Should you decide
this is indeed necessary, be careful. One small error may cause
X to fail. Any changes to this file will require
restarting X for the changes to take
effect.
Using somebody else's XF86Config file, is generally a
bad idea since they are unlikely to have identical hardware.
xvidtune and Monitor Tuning You probably want to get the most out of your hardware. If
X isn't configured optimally, consider re-running
your vendor's X configuration utility and try to
get better results. It is highly unlikely that you could hurt anything by
experimenting. Most modern monitors now have safeguards that prevent a
meltdown ;-)
If you over-do it though X may not be able to
start. For this reason, I prefer to use the startx way of
starting X (see below) while
experimenting. This way if X
crashes, the display manager (GUI login) will not loop and cause you severe
headaches. startx just gracefully goes back to a text
console screen, where an error message may be visible.
Another way of tweaking monitor related settings is with XFree86's
xvidtune program. This is run interactively and can be
used to adjust various settings (see man page). The simple dialog box has
sliders and buttons that allow user input and adjustment. The top part has
horizontal monitor settings on the left, and vertical settings on the right.
The buttons just below the sliders can be used to adjust each.
This is sometimes used to adjust the viewable screen area, such as to center
it, or increase its size to fill the monitor's viewport. When
xvidtune is launched, it defaults to the current settings.
The bottom left corner has buttons that can Apply new
settings, Test new settings, or Show current
settings (i.e. dump to screen), among other things. Any changes made here are
not saved. If new settings are Applied, it is just for
the current session. Example output of xvidtuneShow:
Vendor: Unknown, Model: Unknown
Num hsync: 1, Num vsync: 1
hsync range 0: 30.00 - 70.00
vsync range 0: 55.00 - 120.00
"1400x1050" 122.00 1400 1488 1640 1880 1050 1052 1064 1082 +hsync +vsync
The last line is the Modeline being used to drive the current
screen. See The XFree86 Video
Timings HOWTO, http://www.linuxdoc.org/HOWTO/XFree86-Video-Timings-HOWTO/index.html,
for more on Modelines.
You can test modifications, and apply them to the current session.
For changes to be made permanent, they will have to be added manually to
the Monitor section of XF86Config (or
XF86Config-4 for v.4.x) with a text editor.
xvidtune will dutifully warn of you of the hazards of
playing with the monitor settings. It is unlikely you can hurt anything
with modern monitors. But it is best used to make minor adjustments. Use at
your own risk!
Running X Starting an X session is typically done in one of
two ways: the X session is started via a display
manager (like xdm), and the user logs in at a GUI screen.
Or, the user starts X manually after logging in to
a text console. The latter is typically done with the
startx command, which is a simple shell script wrapper
for xinit. X runs with root
privileges in either case, since it needs raw access to hardware devices.
Typically, which method is used, is determined by the system
runlevel. The default runlevel to launch at boot is
generally set in /etc/inittab on Linux:
# Run xdm in runlevel 5
x:5:respawn:/etc/X11/xdm -nodaemon
That would start xdm, and thus
X, at runlevel 5. It will respawn,
if it dies or is stopped for any reason. You can also use the
init command to change runlevels without
rebooting (see man page).
Let's look briefly at both approaches, and then some additional configuration
to set up the user's working environment.
startxstartx will start X by first
invoking xinit. By itself, this would put you at a blank,
fuzzy looking, bare-bones desktop with no Window Manager loaded.
xinit basically takes two sets of command line
arguments: client specifications (programs to run, etc), and server
specifications (X server options), separated by --. If no
client program is specified on the command line, xinit
will look for a .xinitrc file in the user's home
directory, to run as a shell script. If found, this then would in turn run
whatever user specified commands to set up the environment, or launch
programs that the file contained. If this file does not exist,
xinit will use the following initial command:
xterm -geometry +1+1 -n login -display :0
If no .xserverrc is found in the user's home directory,
X itself will be started with the following command:
X :0
As you see, this is not overly helpful as it just launches one
xterm. The startx
shell wrapper provides additional functionality and flexibility to
xinit. startx will invoke
xinit for us, and provide some simple configuration
options as well. You can also issue commands such as the following, for
instance:
startx -- -dpi 100 -depth 16 #force X to 100 dots per inch
#and colordepth of 16 (X v4 syntax)
Anything after the double dashes are passed as arguments directly to the X
server via xinit. In this example, you can force
X to the resolution of your preference, and still
have it use the configuration files we will cover later in this document. See
the Xserver man page for more command line options.
Instead of issuing the same command line every time, it is easier to use the
configuration files to store this type of information for us.
If you take a look at the startx script
(/usr/X11R6/bin/startx on my system), you see it uses
two default configuration files to help set up the
X environment: xinitrc and
xserverrc. It looks first in
/etc/X11/xinit/, for the system wide files. It then
checks the user's home directory for similar files, which will take
precedence if found. Note that the latter are Unix style dot files
(e.g. ~/.xinitrc), and are executable shell scripts.
You normally would not want to edit the system wide files, but you can freely
copy these to your home directory as a starting point, or just start from
scratch. As you can tell by the names, one helps set up the X server, and one
sets up xinit by executing commands, preparing the
environment and possibly starting client programs like
xterm or a Window Manager (yes, it's a client too).
xserverrc As with all XFree86 configuration files, this is a plain text file, and is
usually a simple, one line statement to start the X server. It can include
any valid command line options supported by your X
installation. If you always start X with your own
options, this should be easier than typing the options each time. One
possible ~/.xserverrc:
exec X :0 -dpi 100 -nolisten tcp
This will start X on display :0, the first
display, at a dots-per-inch resolution of 100, and disables
TCP connections. See the Xserver man page for other valid options. This is
just an example.
xinitrcxinitrc is used to set up a suitable
X environment, and to launch other programs, a.k.a
clients that we may want available as soon as
X is started. You likely have a system wide
xinitrc to start a predefined set off programs. To
customize this, create your own in your home directory. Name it
.xinitrc, make sure it is an executable script, and
chmod +x. An example (slightly modified from the original
on my system):
#!/bin/sh
# $XConsortium: xinitrc.cpp,v 1.4 91/08/22 11:41:34 rws Exp $
userresources=$HOME/.Xresources
usermodmap=$HOME/.Xmodmap
# merge in defaults and keymaps
if [ -f $userresources ]; then
xrdb -merge $userresources
fi
if [ -f $usermodmap ]; then
xmodmap $usermodmap
fi
if [ -z "$BROWSER" ] ; then
# we need to find a browser on this system
BROWSER=`which netscape`
if [ -z "$BROWSER" ] || [ ! -e "$BROWSER" ] ; then
# not found yet
BROWSER=
fi
fi
if [ -z "$BROWSER" ] ; then
# we need to find a browser on this system
BROWSER=`which lynx`
if [ -z "$BROWSER" ] || [ ! -e "$BROWSER" ] ; then
# not found yet
BROWSER=
else
BROWSER="xterm -font 9x15 -e lynx"
fi
fi
export BROWSER
# start some nice programs
if [ -f $HOME/.Xclients ]; then
exec $HOME/.Xclients
else
xclock -geometry 50x50-1+1 ent
xterm -geometry 80x50+494+51 ent
if [ -f /usr/X11R6/bin/fvwm ]; then
exec fvwm
else
exec twm
fi
fi
#eof
Briefly, what this script does, is set up our working environment, with
xmodmap (keyboard) and xrdb
(application resource settings). More on these below. Then the shell variable
$BROWSER is set for a GUI environment (Netscape in this
example) so that any applications that might expect this, have a reasonable
choice available. Then the presence of the file Xclients
is checked, both as a system wide file and in the user's home directory. In
this particular example, this is where any client applications are to be
started, including a Window Manager (see below). These could just have as
easily been started here if we had wanted to. If an
Xclients file can't be found, then a Window Manager is
started for us. Either fvwm, if available, or XFree86's
minimalist twm if not. If for some reason, neither of
these can be started, the script would exit, and X
would fail to start.
Xclients Everything up to this point has followed pretty much a standard and
predictable sequence of events. To summarize, we have invoked
startx, which in turn invoked xinit,
which has parsed xinitrc for initial settings. Most
Linuxes should follow this same sequence, though the various values and
settings may differ.
We now are at the last link in the chain where the user normally would
specify his or her preferences, including the Window Manager and/or
desktop environment to be used. The system will provide sane, though possibly
uninteresting, defaults if the user has not done so. Presumably, this is why
you are here ;-)
The Window Manager, or desktop environment, is typically the last application
started. If you want other programs (like xterm) started,
they should be started before the Window Manager and
backgrounded with an ent. This can all be
done in the user's ~/.xinitrc. Or as in the above
example, the actual applications are started from yet another script. Let's
look at one short, hypothetical such script, .Xclients:
#!/bin/bash
# ~/.Xclients, start my programs.
xset s off s noblank
xset m 30/10 4
xset r rate 200 40
xscreensaver ent
rxvt -geometry 80x50-50+150 ent
echo Starting Window Manager...
if [ -x /usr/X11R6/bin/wmaker ]; then
echo `date`: Trying /usr/X11R6/bin/wmaker... |tee -a ~/.wm-errors 2entent1
exec /usr/X11R6/bin/wmaker entent ~/.wm-errors 2entent1
fi
echo `date`: Failed, trying fvwm... |tee -a ~/.wm-errors 2entent1
# let's try regular fvwm (AnotherLevel doesn't work with fvwm1).
if [ -n "$(type -path fvwm)" ]; then
# if this works, we stop here
exec fvwm entent ~/.wm-errors 2entent1
fi
echo `date`: Failed, trying twm... |tee -a ~/.wm-errors 2entent1
# wow, fvwm isn't here either ...
# use twm as a last resort.
exec twm entent ~/.wm-errors 2entent1
# Dead in the water here, X will exit as well, sigh...
echo `date`: Unable to start a Window Manager ... |tee -a ~/.wm-errors 2entent1
# eof
This really isn't so different than what xinitrc was
doing at all. We added a few wrinkles, including starting a screen saver, a
different terminal emulator that this user prefers (rxvt),
with even more setting up of the environment (monitor, mouse and keyboard) using
xset this time, and a different Window Manager than was
available with the system defaults. This is in the user's home directory, so
it won't be overwritten during upgrades too.
Actually, X has already started at this point, and
we are just putting the finishing touches on the configuration. Notice the
Window Managers are not backgrounded with ent
here. This is important! Something has to run in the foreground, or
X will exit. We didn't start a desktop environment
in this example, like KDE or
GNOME, but if we did, this final application
would have to be gnome-session or
startkde instead. Since we are rolling our own here, if we
wanted to change Window Managers, all we have to do is edit this file, and
restart X. Vendor supplied configurations may be
more complex than this, but the same principles apply.
As an afterword, do not think that any initial client applications
must be started as we've done here. This is how it has
been traditionally done, and some may prefer this approach. Most window
managers have their own built-in ways to start initial programs, as do
KDE and GNOME. See
the respective documentation.
Display Managers The other, more common, approach is the GUI log-in, where
X is running before log-in. This is done with the
help of a display manager, of which there are various
implementations. XFree86 includes xdm (X Display Manager)
for this purpose, though your distribution may use one of the others such as
gdm (GNOME) or kdm
(KDE).
Display managers really do much more than enable GUI style log-ins. They
are also used to manage local as well as remote displays on a
network. We won't get into details on this here, but it is nicely covered in
the Remote X Apps Mini HOWTO and the XDMCP
HOWTO (see the links section). For
our purposes here, they provide similar services to getty
and login, which allow users to log into a system and
start their default shell, but in a GUI environment.
Here is an example of a more advanced usage of what else a display manager
might be used for, from Diego Zamboni:
I have two X sessions running with different resolutions. I switch between
them depending on whether my laptop is connected to an external monitor or
using its own LCD display.
Here's my /usr/lib/X11/xdm/Xservers file that initiates
both displays:
:1 local /usr/X11R6/bin/X :1 -layout 1024x768
:0 local /usr/X11R6/bin/X :0 -layout 1600x1200
Then I have 1024x768 and 1600x1200 defined as
server layouts in my
/etc/X11/XF86Config-4, as follows:
Section "ServerLayout"
Identifier "1600x1200"
Screen "Screen0" 0 0
InputDevice "Mouse0" "CorePointer"
InputDevice "Keyboard0" "CoreKeyboard"
EndSection
Section "ServerLayout"
Identifier "1024x768"
Screen "Screen1" 0 0
InputDevice "Mouse0" "CorePointer"
InputDevice "Keyboard0" "CoreKeyboard"
EndSection
## snip ...
Section "Screen"
Identifier "Screen0"
Device "S3 Savage/MX"
Monitor "Monitor0"
DefaultDepth 16
Subsection "Display"
Depth 16
Modes "1600x1200" "1280x1024" "1024x768"
EndSubsection
EndSection
Section "Screen"
Identifier "Screen1"
Device "S3 Savage/MX"
Monitor "Monitor0"
DefaultDepth 16
Subsection "Display"
Depth 16
Modes "1024x768" "800x600"
EndSubsection
EndSection
Note the use of Identifiers here. Diego is starting two
separate displays here. Then he can choose which one he
wants when he logs in.
Most display managers are derived from XFree86's venerable
xdm, and add their own enhancements. Let's look at the
most popular ones briefly.
xdmxdm can be configured with configuration files located in
/etc/X11/xdm/,
/usr/X11R6/lib/X11/xdm, or similar locations depending
on your system. These are system wide files. The file
xdm-config is the main configuration file, and mostly
describes where to find secondary configuration files:
! $XConsortium: xdm-conf.cpp /main/3 1996/01/15 15:17:26 gildea $
DisplayManager.errorLogFile: /var/log/xdm-errors
DisplayManager.servers: /etc/X11/xdm/Xservers
DisplayManager.accessFile: /etc/X11/xdm/Xaccess
! All displays should use authorization, but we cannot be sure
! X terminals will be configured that way, so by default
! use authorization only for local displays :0, :1, etc.
DisplayManager._0.authorize: true
DisplayManager._1.authorize: true
! The following three resources set up display :0 as the console.
DisplayManager._0.setup: /etc/X11/xdm/Xsetup_0
DisplayManager._0.startup: /etc/X11/xdm/GiveConsole
DisplayManager._0.reset: /etc/X11/xdm/TakeConsole
!
DisplayManager*resources: /etc/X11/xdm/Xresources
DisplayManager*session: /etc/X11/xdm/Xsession
!
! SECURITY: do not listen for XDMCP or Chooser requests
! Comment out this line if you want to manage X terminals with xdm
DisplayManager.requestPort: 0
The ! denotes comments. The command that starts the X server
is in /etc/X11/xdm/Xservers in this particular example
as defined by DisplayManager.servers, and is the equivalent to
xserverrc that was used for startx X
server start up commands, but the syntax is slightly different here. The
contents of /etc/X11/xdm/Xservers on my system are simply:
:0 local /usr/X11R6/bin/X
This starts X on the first local display
(designated by 0). Any special command line arguments that you want to add go
here at the end.
Below is a sample /etc/X11/xdm/Xsetupent0 which is
used to configure the log-in screen only. Notice that we're using a shell
script here, and it's calling xv (a graphics display
program) to set the background to a nice image (instead of the boring black
and white background pattern), and if that fails,
xsetroot is then invoked to at least try to set the
background to a nicer blue color. This does not configure the login widget
itself -- just other things that might be wanted on the screen during login.
ent!/bin/sh
xconsole -geometry 480x100-0-0 -daemon -notify -verbose -fn \
'-schumacher-clean-medium-r-*-*-10-*-*-*-*-*-*-*' -exitOnFail ent
/usr/X11R6/bin/xv -quit -root /usr/share/pixmaps/Backgrounds/InDreams.jpg \
|| xsetroot -solid darkblue
/etc/X11/xdm/Xresources controls the X
resources used during log in. In this context, resources
are user preferences for such items as fonts and colors (described in more
detail below). Below is a snippet that sets up fonts for the log-in widget:
#if WIDTH ent 800
xlogin*greetFont: -adobe-helvetica-bold-o-normal--24-240-75-75-p-138-iso8859-1
xlogin*font: -adobe-helvetica-medium-r-normal--18-180-75-75-p-103-iso8859-1
xlogin*promptFont: -adobe-helvetica-bold-r-normal--18-180-75-75-p-103-iso8859-1
xlogin*failFont: -adobe-helvetica-bold-r-normal--18-180-75-75-p-103-iso8859-1
#else
xlogin*greetFont: -adobe-helvetica-bold-o-normal--17-120-100-100-p-92-iso8859-1
xlogin*font: -adobe-helvetica-medium-r-normal--12-120-75-75-p-69-iso8859-1
xlogin*promptFont: -adobe-helvetica-bold-r-normal--12-120-75-75-p-69-iso8859-1
xlogin*failFont: -adobe-helvetica-bold-o-normal--14-140-75-75-p-82-iso8859-1
#endif
As you can see this is using helvetica as the preferred font, with different
point sizes and dots per inch depending on the screen size. This is
customizable to suit individual needs. (See below for more on understanding X
font naming conventions.) Various other aspects can similarly be configured.
/etc/X11/xdm/Xsession is the rough equivalent to
xinitrc for startx. It will similarly
set up a default environment for keyboard, etc. And can also start either
KDE or GNOME, and other
X client programs. This is the system wide
configuration file. It should also check the user's home directory for
~/.xsession, and possibly
~/.Xclients, which would contain the user's preferred
environment and start up programs, just as ~/.xinitrc
did with startx. Again, the files in a user's home
directory may be created or modified by the user any time and must be
executable shell scripts.
We won't include an ~/.xsession example here, since it
would be very similar to the ~/.xinitrc and
~/.Xclients examples above.
We've looked only briefly at the main xdm configuration files.
Be sure to read the man page, and look at what is installed locally, for more
information. Let's look now at gdm and kdm.
We'll just highlight significant differences, since they essentially provide
the same functionality.
gdmgdm is the default display manager for
GNOME. gdm was written
from scratch, but functions similarly to xdm. The main
configuration file is gdm.conf, typically located as
/etc/X11/gdm/gdm.conf. This is quite different looking
than xdm-config. Comments are denoted with a
#, and the file has sections, with section headers enclosed
in square brackets. The command to start X is in
the [servers] section:
[servers]
0=/usr/bin/X11/X
#1=/usr/bin/X11/X
Notice this has potentially two displays set up, but the second one is
commented out. Add any additional X startup
options here, e.g. -dpi 100. The log-in screen and log-in
widget are configured in the [greeter] section.
Start up clients and programs are determined by the SessionDir
statement in the [daemon] section. On my installation, this
points to /etc/X11/gdm/Sessions/, which contains several
short scripts. If I look at my Default script, it
actually executes /etc/X11/xdm/Xsession, which in turn
would execute ~/.xsession, if present. So at this final
stage, gdm acts very much like xdm.
GNOME includes the gdmconfig
utility to control many aspects of gdm behavior.
kdmkdm is the display manager from KDE.
The main configuration file for kdm is
kdmrc and is typically installed
as /etc/kde/kdm/kdmrc. As is the case with
gdm.conf, kdmrc uses
# for comments, and has sections with section headers in
similar square brackets. kdm configuration can also be
edited with the kcontrol utility.
The visible desktop is configured in the [Desktop*]
section(s), and by the Setup directive which should point to a
file like /usr/share/config/kdm/Xsetup or
/etc/X11/xdm/Xsetup_0. This will accomplish the same
thing as xdm's Xsetup_0 does: namely
running any programs the user might want such as xconsole.
The command to launch the X server is the Xservers directive
in the [General]. Again, this should point to a file such as
/etc/X11/xdm/Xservers, and uses the same syntax as
xdm:
:0 local /usr/X11R6/bin/X
Any command line options for the X server, go here.
The login widget itself is configured in the [X-*-Greeter]
section(s). Compiled in defaults are used if the user does not specify any.
KDE includes the kdmdesktop
utility to control some aspects of kdm behavior, mostly
just the login background.
More X Configuration Before taking a look at various configuration mechanisms for X servers and
clients, it should be noted that the advent of Desktop Environments like
KDE have become popular in part because they can
control much of the user interaction configuration themselves with nice,
user friendly GUI controls. And in fact,
the compliant applications that are part of the respective Desktops will be
best configured through the Desktop's configuration tools, or the
application's own GUI configuration methods. So, for instance,
gtop, a GNOME client
application, is best configured via GNOME or
gtop's own menus. But this is not true of all
X applications.
X Resources The X server can store various configuration values for client programs
so they are readily available when needed. If the application supports this,
it will use these as defaults whenever that program is invoked. These are
known as Resources, and are often used to define user preferences
on a per application basis for fonts, colors, screen placement (geometry) and
various other attributes. This makes it easy to customize applications.
Resources are specified as text strings (e.g. Netscape*blinkingEnabled:
False) that can be read from disk in various places when
X is starting, or even interactively defined on the
command line. Program components are named in a hierarchical fashion, with
each object in the hierarchy identified by a class as well as an instance
name. At the top level of the hierarchy is the class and instance name of the
application itself. Typically, the class name of the application is the
same as the program name, but with the first letter capitalized (e.g. Vim or
Emacs) although some programs that begin with the letter X
also capitalize the second letter for historical reasons (e.g. XTerm).
Each definition will specify a class (or instance), with corresponding
resource and value. Below this in the hierarchy are the various attributes
that make up the definable aspects of the application.
Traditionally, most X programs were configured
this way. This is not as true today with the advent of Desktop Environments
which often have their own configuration mechanisms.
As an example, say we prefer to run xterm with a blue
background. So if we run it from the command line, we would run it as:
xterm -bg blue ent
If this is our preference, it would be easier to put this preference in a
file somewhere, and have the system use our preference. That way whenever we
started xterm, it would use our preferred value, and we
wouldn't need the command line options (unless as an override).
The basic X resource syntax is expressed like:
entprogramententbindingententwidgetententbindingententwidgetentent...ententresourceent:entvalueent
Which, in real life, typically looks something like:
xterm*fontMenu*background: darkblue
It should be obvious what this does. The use of * in the
definition, is called a loose binding and acts as a
wild-card. Meaning there may be gaps in the widget hierarchy. For instance:
xterm*background: darkblue
This would also give a dark blue background for the xterm
fontMenu, but also any other xterm properties that also have a
background attribute (e.g. window background, etc), no matter
where they may be in the widget hierarchy. Similarly:
*background: darkblue
This would define the background for any and all programs that support it -- not just
xterm. Using a . in place of a
* would be more precise, and will not allow for wild-card gaps
in the hierarchy. Also, the application must support the particular widget
attribute. Background is a fairly safe bet, but many
applications will have more specialized resources that are not so obvious. It
is best to check local documentation (man pages, etc), or see if an
application has an included examples. For instance, Netscape
generally comes with an Netscape.ad file that has an extensive
set of resource definitions that can be customized.
X resources are typically stored in more than one
place (see below) and are processed by the xrdb command (see man page).
App Defaults One way of storing preferred application resources is via files named for the
application in an app-defaults directory. For instance, on my
system, these are in /usr/X11R6/lib/X11/app-defaults/,
though this may vary according to options your vendor has chosen. This
directory contains a number of files for such well known
X applications as xterm,
xclock, xcalc,
xload, and so on. All in all, it is a relatively small
number of applications in the overall scheme of things. So not all
applications use this scheme. In fact, most do not.
Each file will contain resource definitions for that application. The X
server loads these by itself during start up. A brief example from
XTerm-color:
! $XFree86$
#include "XTerm"
*VT100*colorMode: on
*VT100*dynamicColors: on
! Uncomment this use color for underline attribute
!*VT100*colorULMode: on
!*VT100*underLine: off
! Uncomment this to use color for the bold attribute
!*VT100*colorBDMode: on
*VT100*color0: black
*VT100*color1: red3
*VT100*color2: green3
*VT100*color3: yellow3
*VT100*color4: blue3
*VT100*color5: magenta3
*VT100*color6: cyan3
*VT100*color7: gray90
*VT100*color8: gray30
*VT100*color9: red
*VT100*color10: green
*VT100*color11: yellow
*VT100*color12: blue
*VT100*color13: magenta
*VT100*color14: cyan
*VT100*color15: white
*VT100*colorUL: yellow
*VT100*colorBD: white
This is mostly various color definitions. The application classname is not
explicitly stated, and is assumed from the filename. So think of each line as
starting: XTerm-color*. Also, notice at the top, the
#include "XTerm" line, which includes the
resource definitions for XTerm, a much longer file with a
more diverse set of definitions. (Not included due to length, but worth
looking at.) These files provide system wide defaults, and generally
speaking, would not normally be edited by the user.
Xdefaults Another common method of reading in resource preferences, is with an
Xdefaults file. Or, sometimes the naming
scheme may be Xresources instead. This may exist as a
system wide file, such as /etc/X11/Xresources.
Of course, the user is free to create a personal version in his home
directory, e.g. ~/.Xdefaults. The user's version will
over-ride any system wide settings, and will remain after system upgrades.
Obviously, this is the place to put your own preferences.
Xresources files are read into the resource database
with the xrdb command. Example:
xrdb -merge ~/.Xresources
This can be done interactively at the command line, or placed in a script and
run automatically as the X session is started. In
the case of system wide files, this should be taken care of by the vendor
supplied start up scripts. Generally, such scripts will also check the user's
home directory as well (see the xinitrc example above).
So probably all that need be done, is to create the file with a text editor.
Here's an example to illustrate a very few of the many things that might
be done with an .Xdefaults file:
! This is a comment ;-)
#ifdef COLOR
*customization: -color
#endif
!! Let's cast a wide net, for any app supporting these
! Blink instead of beeping
*visualBell: True
*scrollTtyOutput: False
*scrollKey: True
! See Netscape.ad for many settable resources
Netscape*noAboutSplash: True
Netscape*documentFonts.sizeIncrement: 5
Netscape*documentFonts.xResolution*iso-8859-1: 120
Netscape*documentFonts.yResolution*iso-8859-1: 120
netscape-navigator*geometry: 960x820+240+140
emacs*Background: DarkBlue
emacs*Foreground: Wheat
emacs*pointerColor: Orchid
emacs*cursorColor: Orchid
emacs*bitmapIcon: on
emacs*font: 10x20
! GVim colors, etc
!! GTK versions of gvim will not use all these.
Vim*useSchemes: all
Vim*sgiMode: true
Vim*useEnhancedFSB: true
Vim.foreground: Black
!Vim.background: lightyellow2
Vim*background: white
! geometry: width x height
Vim.geometry: 88x40
Vim*font: -misc-fixed-medium-r-normal--20-200-75-75-c-100-iso8859-15-*5
Vim*menuBackground: yellow
Vim*menuForeground: black
rxvt*backspacekey: ^?
rxvt*background: Black
rxvt*foreground: wheat
rxvt*cursorColor: Orchid
rxvt*geometry: 100x18+40+300
rxvt*title: Linux
rxvt*reverseVideo: false
!rxvt*backgroundPixmap: ~/penguinitis.xpm
rxvt*scrollBar: true
rxvt*reverseWrap: true
rxvt*font: -*-lucidatypewriter-medium-*-*-*-14-*-*-*-*-*-*-*
rxvt*fullCursor: true
rxvt*saveLines: 1500
rxvt*menu: ~/rxvt.menu
XTerm*saveLines: 1500
! Do not clear the screen after the program exits
XTerm*VT100*titeInhibit: true
! Fix up xterm's keybindings
xterm*VT100.translations: #override \
entKeyentBackSpace: string(0x7F) \n\
entKeyentInsert: string(0x1b) string("[2~")\n\
entKeyentDelete: string(0x1b) string("[3~")\n\
entKeyentHome: string(0x1b) string("[1~")\n\
entKeyentEnd: string(0x1b) string("[4~")\n\
entKeyentPage_Up: string(0x1b) string("[5~")\n\
entKeyentPage_Down: string(0x1b) string("[6~")\n\
entKeyPressentPrior : scroll-back(1,page)\n\
entKeyPressentNext : scroll-forw(1,page)
! Ghostview
Ghostview*Font: *-helvetica-bold-r-normal--12-*-*-*-*-*-*
Ghostview*BorderColor: white
Ghostview*Text*Font: rk14
Ghostview*Background: #d9d9d9
!Ghostview*Foreground: white
ghostview.form.pageview.page.background: white
ghostview.form.pageview.page.foreground: black
.ghostview.zoom.form.page.background: white
.ghostview.zoom.form.page.foreground: black
! xscreensaver !
! Time out after 12 minutes, cycle mode after each 2
xscreensaver.timeout: 12
xscreensaver.cycle: 5
! Run low priority, and fade between modes
xscreensaver.nice: 12
xscreensaver.fadeSeconds: 2
XFontsel.menu.options.showUnselectable: False
Hopefully, these few examples will give you some ideas to build on.
X does not need to be restarted if
xrdb is used interactively from the command line after
making changes. The effects are immediate.
Resources are sometimes available also as command line options. See below.
Command line options will over-ride any existing resource definitions.
xmodmap, the Keyboard and Mice The keyboard and mouse, as well as other possible input devices, are defined
in XF86Config (or XF86Config-4).
There is a keyboard layout that is defined based on the preferred language:
Section "InputDevice"
Identifier "Keyboard0"
Driver "keyboard"
Option "XkbLayout" "us"
EndSection
This gives us our default keyboard layout. Valid layout labels are listed in
/usr/X11R6/lib/X11/xkb/symbols. Also, the
setxkbmap utility can be used to change this
interactively.
X is highly customizable, and we can modify the
keyboard and mouse pointer mappings to suit our own preferences. The utility
to do this is xmodmap (see man page). You don't like where
the capslock key is? So move it ;-)
Like xrdb, xmodmap can be run from the
command line. Or, preferred settings can be stored in a file. Typically this
is ~/.Xmodmap, or similar. If your
X start up files don't parse this, then edit as
appropriate so that they do (probably from ~/.xinitrc or
~/.xsession).
You can view your current key and mouse mappings with: xmodmap -pk
-pp |less. This will print out all active keycode
values, with corresponding keysym values, and any keysym names
that xmodmap knows about (e.g. BackSpace).
And should also give you an idea of how xmodmap
understands key and mouse events. There are two keysyms per keycode. The
second is the shifted value. XFree86's xev utility can be
used to dump a lot of information on key-presses and mouse events
interactively. Pay attention to the keycode value. That is
what you will need to know in order to re-map.
xmodmap is often used to make minor keyboard adjustments,
like proper Backspace/Delete mapping. Or can be used make major adjustments
such as for international mappings. You can only re-map keys and mouse events
-- you cannot assign macros to key events (your Window Manager or Desktop
might have some of this functionality).
Setting up international keyboards in nicely discussed in http://www.linuxdoc.org/HOWTO/mini/Intkeyb/index.html.
Also, a search of http://google.com/linux
will turn up many creative examples.
The man page has many brief examples of various usages. Here is what an
one hypothetical ~/.Xmodmap might look like:
! /home/hal/.Xmodmap, last change 10/03/01
!
! Force backspace to 22 and Delete to 111
keycode 22 = BackSpace
keycode 111 = Delete
!
! My keyboard handles right and left Alt differently. Make the
! Right act like the Left to avoid digital gymnastics.
keycode 63 = Alt_L
keycode 113 = Meta_L
!
! Hard-code the keypad to numeric values as if numlock is always on
! since I never use it for anything else.
keycode 79=7
keycode 80=8
keycode 81=9
keycode 83=4
keycode 84=5
keycode 85=6
keycode 87=1
keycode 88=2
keycode 89=3
keycode 90=0
keycode 91=period
keycode 86 = plus
! deactivate Num_Lock key since we don't need it now.
keycode 77 =
!
! My capslock is next to tab. I hit it by mistake sometimes,
! and don't use it anyway. So make capslock act like Tab.
keycode 66 = Tab
clear lock
!
! Reverse mouse buttons for left-handed people
pointer = 3 2 1
As with many XFree86 files, the ! represents a comment.
Another possible use, is to redefine those annoying Windows
keys to something useful. Hopefully this gives an idea of some things one
might want to do to make the keyboard more agreeable to us.
Speaking of the Numlock key, X
will typically disable this when it starts up. No matter how you have the
BIOS set up, or Linux set up before X starts. So the
trick above is one way. There is also a utility available as either
numlockx, or
setnumlock, that can be found on the 'Net, if
your distribution does not include one or the other. This can be put in a
start up file to turn Numlock on automatically if you'd
prefer.
Window Managers and Desktop Environments will also allow customization of the
keyboard and mouse (as long as it is recognized correctly by
X). This may be an easier way to configure certain
customizations.
Special Key Mappings There are several special key mappings traditionally used in
XFree86.
Ctrl-Alt-BackSpace - Will kill the X server process in an orderly
fashion. This is a quick, easy, legitimate way to restart
X. Note it does not restart the display
manager (if used) -- just X itself.
Ctrl-Alt-Fx - where x corresponds to a valid tty number
(typically 1-6). This is typically used to jump to a text console login,
while X remains running. To get back to
X, then it is Alt-Fx. In this
case, x represents one plus the last tty (e.g. Alt-F7 if
there are six available ttys).
Ctrl-Alt-keypad+ and Ctrl-Alt-keypad- - That is the plus and minus keys on
the keypad. This will cycle through any existing valid screen resolution
Modes, e.g. 1024x768 -ent 600x800. Note the actual screen
size is the same -- just the view and resolution changes. Not all that
useful for most purposes. You cannot permanently change the screen
resolution without restarting X.
It's possible your Window Manager, Desktop Environment or other system
component may trap these, and alter the standard behavior. In addition, the
Ctrl-Alt-Delete may be trapped as well. This should shut
X (and the system) down orderly, if it is
available.
Mice and Pointers As mentioned, Linux and Unix make heavy use of three mouse buttons. If a
mouse only has two buttons, then the third (i.e. the middle) button can
be simulated by pressing both buttons simultaneously. This is a
configuration option set in XF86Config as the
Emulate3Buttons directive:
Section "InputDevice"
Identifier "Mouse0"
Driver "mouse"
Option "Device" "/dev/mouse"
Option "Protocol" "PS/2"
Option "Emulate3Buttons" "on"
EndSection
When all is said and done, a third button is quite handy and I would personally recommend
having one. On wheeled mice, the wheel acts as the third
button, if pressed. Many standard wheel mice seem to work with the
IMPS/2 protocol option.
Specifically, the third button (middle) is the paste button in
virtually all Linux applications. Copy and paste works a little different in
Linux. The left button is the copy button. Just hold it down, and drag over
text. It is automatically copied to the Xclipboard. Then, the middle button will paste from there. A
very simple process. A double-click should copy individual words, and a
triple-click individual lines of text. If for some reason, this does not
work, it is either a poorly implemented application, or a bug of some kind.
Some older versions of Netscape were not
consistent about this, for instance. To paste from the keyboard, this should
be shift+insert.
Drag and Drop is not natively supported by
X itself. But, is implemented by some toolkits and
Desktop Environments. One should not expect this to work with non-compliant
applications (i.e non-KDE aware applications in
KDE for example).
xsetxset is yet another XFree86 utility to set user
preferences. xset is a bit of a catch-all and is used
to change various, unrelated X server settings. Mostly this is a command
line way of configuring some of the same things that are defined in
XF86Config (but not everything!).
Common usages of xset are to set DPMS on or off and
preferred intervals, to dynamically change the FontPath or re-read it, to
control keyboard LEDs, to adjust mouse (or other pointer) movement speed,
set keyboard autorepeat and repeat rates, and
to control X's built in screen blanking. See the
man page, of course, for detailed explanations, and other
xset usages.
Again, xset can be used interactively from the command
line. But most often preferred settings are stored in one of the start up
configuration files, like .xinitrc or
.xsession. A very brief example:
# Turn off screen blanking
xset s off
# Enable DPMS energy saving
xset +dpms
# Tweak the rodent
xset m 30/10 4
# Speed up keyboard
xset r rate 200 40
Your desktop may have a GUI front-end for xset.
Fonts and Colors Understanding fonts and colors can be more complex in
X than on other platforms. Fonts DemystifiedX knows about various font types, including
bitmaps, Type 1, and as of v4.x, TrueType. The X server can either handle
fonts itself, or sometimes this duty is forked to a font server (of which
there are several). xfs (X Font Server) is the most common
font server in use on Linux.
A font server is not required, as X can handle
most font rendering itself. Font servers are traditionally used for serving
fonts to multiple hosts on a network, but sometimes are also used to provide
enhanced functionality. Additionally, a font server may provide a modest
performance boost by off-loading font rendering to a separate process.
X knows about fonts according to fonts that are in
the FontPath. This is set initially in
XF86Config. If the X server is handling font duties
itself (i.e. no font server), this will be a list of directories that contain
font files, like:
FontPath "/usr/X11R6/lib/X11/fonts/misc:unscaled"
FontPath "/usr/X11R6/lib/X11/fonts/100dpi:unscaled"
FontPath "/usr/X11R6/lib/X11/fonts/75dpi:unscaled"
FontPath "/usr/X11R6/lib/X11/fonts/Type1"
FontPath "/usr/X11R6/lib/X11/fonts/misc"
FontPath "/usr/X11R6/lib/X11/fonts/100dpi"
FontPath "/usr/X11R6/lib/X11/fonts/75dpi"
If a font server is being used, the FontPath will point to the
socket where the font server is serving (this is just one possible example):
FontPath "unix/:7101"
In this latter case, the actual font directories that are available will be
configured with the font server (see local documentation), which will use a
similar directory type scheme as shown for XF86Config.
Once suitable fonts have been installed, they must be
prepared. For most fonts, this means running the
mkfontdir utility (see man page) in the directory where
the fonts are (as root). Type 1 and TrueType require additional steps (see
below). Your vendor has done this for any fonts that were included with your
distribution. So, this will only need to be done for fonts that you add. For
newly added fonts to become visible to X,
you will need to run the appropriate
xset commands to either modify the existing FontPath, or
re-read it (see man page). Or, re-initialize your font server.
Example: Preparing fonts, and re-initializing font server after adding new
fonts:
su
entpasswordent
mkfontdir /usr/X11R6/lib/X11/fonts/my_new_fonts/
/etc/init.d/xfs restart
The first command may not be necessary on newer distros (since it's done by
the init script in some cases). And the font server configuration would need
to be modified, if this is a new directory. Example: re-initializing with no
font server:
su
entpasswordent
mkfontdir /usr/X11R6/lib/X11/fonts/my_new_fonts/
xset +fp /usr/X11R6/lib/X11/fonts/my_new_fonts/
xset fp rehash
The xset +fp would not be necessary if the
directory is already part of the FontPath.
xlsfonts | less can be used to list what fonts are known,
and thus available, to X and its clients. Run
xlsfonts | less, and you also can get an idea of the font
definition as understood by X. Font resources are
specified quite explicitly, and it may seem complex at first. The X
Logical Font Description (XLFD) is the full
description for any given font. The XLFD looks like:
-adobe-helvetica-medium-r-normal-*-*-120-*-*-p-*-iso10646-1
Where each field, left to right is:
fndry - font foundry, the company or individual
which made the font.
fmly - font family, the popular nickname of the font
wght - font weight (bold, medium, etc.)
slant - font slant (italics, oblique, roman
(normal), etc.)
sWdth - font width (normal, condensed, extended, etc.)
adstyl - additional style (sans serif, serif, etc.)
pxlsz - pixel size, the number of pixels
vertically in a character
ptSz - approximate point size of the text
(similar to pxlsz)
resx - horizontal resolution, in dpi
resy - vertical resolution, in dpi
spc - spacing, only useful, apparently, in the
Schumacher fonts
avgWidth - average character width of the font
rgstry - the recognized registry that lists
the font
encdng - nationality encoding
The * acts as a wild-card character. In fact, if not every
field is specified, the X server will take the first match it finds in
the FontPath. This is why it is best to order the FontPath with preferred
fonts coming first since some programs will deliberately specify fonts
loosely so that your system has some discretion.
The program xfontsel (X
Font Selector) may be useful. Try launching it now. You will see
nothing helpful in the main window at first, but try holding the left button
down on the fndry button. If all your fonts are
in order, you will see a menu of selections such as adobe and benth and
bitstream and so forth. Select one such as
benth and you will notice that the font in
the lower window changes to something intelligible. This is the way
fonts are selected with this program; starting from the left, which is the
most general selection, and moving toward the right, to the more specific
options. Selecting an option toward the rightmost end will not make much
sense before the foundry, for instance, is selected, because the options are
generally ordered by their dependence on each other.
When you select from the fmly selection,
you will see most of the options grayed out, and only three remaining. That
means that these three are the only families of font made by this foundry.
Some families appear under more than one foundry, for instance, both
Adobe and Bitstream make a
variation of the Courier font. Now you can select the wght, and so forth. After you get far enough you will
have narrowed it down to the font that you want. You don't necessarily have
to fill in all the options to choose a single font, there's not
that many fonts on your system! The options that you do
not select will be represented by a *
indicating that any option will do in that spot, and gives X some leeway. When you are satisfied with your font selection, hit the select button,
and your selection will be placed in the X
clipboard, ready to be pasted into your document or whatever you are working
on. For example, open an xterm window and
type in something like xterm -font followed by
an opening quotation mark. Then point to that spot on your screen, and click
your middle mouse button (or click both the left and right, if you're
middle-button impaired). This will paste the selection from the clipboard,
which should be the font you just selected. Then enter the closing quote, and
hit Enter. For instance, a nice big xterm with a Courier font specified would look like
this: xterm -font
ent-adobe-courier-medium-r-*-*-14-*-*-*-*-*-*-*ent. If you've found a font you prefer, this can permanently be used by placing the
font definition in the appropriate configuration file (see above).
Note that you can also limit the number of fonts that you want
xfontsel to display with the command line option
-pattern, followed by a quoted font specification, as
discussed above.
The xfd utility is also helpful for examining
individual fonts. If launched with a command line such as xfd
-fn fixed, it will show you the complete character set for that font.KDE and GNOME have
their own utilities that are not quite as obtuse ;-)
Type 1 and TrueType Fonts The fonts provided with XFree86 are of limited use for many of us,
considering that about the only place you'll find fonts of that kind, are
used in the X Window System itself for the most part. Unfortunately many
media junkies, web designers and fontaholics work in operating systems that
rely on other formats. And then, there often does not seem to be much
emphasis by some distributions on making the best of the default fonts
either. Type 1 fonts, most commonly used in conjunction with PostScript document
formats, are the traditional standard in Unix and Linux environments. You
should have a reasonably good starter selection installed already. Or, more
can be found for free on the Internet with considerable ease, and Try ftp://ftp.cdrom.com/pub/os2/fonts/
for starters. Type 1 are scalable fonts, and have many of the same benefits
of the better known TrueType fonts. If you don't have a good selection of
TrueType fonts installed, then Type 1 is what you want for most GUI
applications. But again, this is not standard on other platforms, and can
present problems when viewing documents (e.g. web pages) that are designed
with other platforms in mind.
TrueType fonts started with Apple, and later were licensed by Microsoft. So
people migrating from non-Unix platforms are already familiar with these high
quality fonts. Unfortunately, there are not many quality TrueType fonts under
a suitable license, and thus there are not many included with Linux
distributions. And the ones that are, often are not as high quality. Also
unfortunately, TrueType has become somewhat of a standard on the Web and in
other venues, and not having good TrueType fonts can be a detriment.
XFree86 also seems to render TrueType a little better than Type1.
That's the bad news. The good news is that any TrueType font included with
any version of Windows, or any Windows applications, should work on Linux.
Though you will have to take some additional steps to integrate them. This
particularly helps web browsing where X's
bitmapped fonts just don't scale well.
We won't go into detail on installing and configuring these fonts here, as it
is addressed in depth in other documents. See The Font HOWTO
, ,
for general font information, and Type 1 tips. See The Font De-Uglification
Mini HOWTO, http://www.linuxdoc.org/HOWTO/mini/FDU/index.html,
for various X related font tips, especially TrueType.
Colors Let's go back to our terminal window and try something. Open an
xterm with a command line like the following:
xterm -fg DarkSteelBlue1 -bg red3 ent
Ouch! While that may not be pretty, and you may not do much of your best work
in it, it demonstrates one interesting aspect of X
configuration -- color names. While not particularly precise, this is a nice
way to remember a variety of colors. Note that color names are never
case-sensitive.
The X server will actually deal with color values as a hexadecimal
Red-Green-Blue (RGB) color notation. This would look something like
#0aff0a in hex. Not so easy to remember. But
X gives a more mnemonic way of remembering valid
color definitions. These are stored in a text table, typically as
/usr/X11R6/lib/X11/rgb.txt, and is defined in
XF86Config in the Files section.
If you are interested, have a look with a text editor. There are many, many
shades defined. I count eighty-three shades of blue in mine, for instance. Brief
snip:
176 226 255 LightSkyBlue1
164 211 238 LightSkyBlue2
141 182 205 LightSkyBlue3
96 123 139 LightSkyBlue4
202 225 255 LightSteelBlue1
188 210 238 LightSteelBlue2
162 181 205 LightSteelBlue3
110 123 139 LightSteelBlue4
191 239 255 LightBlue1
178 223 238 LightBlue2
154 192 205 LightBlue3
104 131 139 LightBlue4
This file can be customized should you desire, but this is rarely needed for
most of us. It is important to have though, since some applications depend on
it.
Desktop Environments will have a GUI utility for selecting colors.
Window Managers and Desktops We won't delve into configuring Window Manager's and Desktop Environments.
There is just too much to try to cover in one document. It is important to
realize that the two are not the same. There are many, many Window Managers
available. Window Managers Window Managers are highly configurable. Many aspects of user interaction can
be controlled by the Window Manager.
Some of the most popular Window Managers:
aewm: http://www.red-bean.com/~decklin/aewm/ AfterStep: http://www.afterstep.org/ BlackBox: http://sourceforge.net/projects/blackboxwm Enlightenment: http://www.enlightenment.org/pages/main.html Fluxbox: http://fluxbox.sourceforge.net/ fvwm: http://www.fvwm.org/ IceWM: http://www.icewm.org/ olwm (OpenLook Window Manager):
http://www.plig.org/xwinman/olvwm.html Sawmill: http://sawmill.sourceforge.net/ WindowMaker: http://www.windowmaker.org/ XFce: http://xfce.org/ There are many, many lesser known ones as well.
http://www.plig.org/xwinman/
has an updated list of Window Managers, and related information.
There is always freshmeat too.
GNOME and KDE
both have their default Window Manager, but support other, compliant Window
Managers as well. Your distribution probably has included at least several.
Try them all if you don't already have a favorite. Your distribution probably
also has a method of switching dynamically between Window Managers (and Desktop
Environments too).
Desktop Environments Desktop Environments are not really new, but their popularity has increased
with advent of the two big names: KDE and
GNOME. To a certain extent, the Desktop
Environment functionality overlaps the Window Manager's. They both can be
responsible for the root window background, root window menu, icons,
taskbars, etc. Generally speaking, if a Desktop Environment is running, it is
controlling these aspects. That is the main idea behind them -- to integrate
the various components into a cohesive, consistent whole. Desktop
Environments also add some interoperability and ease-of-use features that a
simple Window Manager cannot. Oh, another point: Desktop Environments also try to do as much
X session configuration as possible. Any of their
compliant clients will more than likely be configured by the Desktop, or have
it's own configuration that conforms to the Desktop's style. This is at
least partly to avoid much of the seemingly helter-skelter text file
configuration we looked at in the above sections, and make life a little
easier for the user.
There is a trade-off in this additional functionality, and that is that it
takes memory and system resources to oversee all this. If you have plenty of
memory and a fast computer, this is no problem. But in low memory situations,
this can cause a slowdown (see the performance
section below). 64M of RAM is probably borderline with either
KDE or GNOME.
So do you need a Desktop Environment? That is up to the user. They are
certainly not required to run X, but do add
features that many users want or expect in a GUI. Which one is better? Ah,
but that is up to you to decide!
KDE has been around longer than
GNOME, and some would say maybe a little more
mature. KDE is based on the QT widget toolkit. A
quote from the KDE home page:
KDE is a powerful Open Source graphical desktop environment for Unix
workstations. It combines ease of use, contemporary functionality, and
outstanding graphical design with the technological superiority of the Unix
operating system. KDE is a mature desktop suite providing a solid basis to an ever growing
number of applications for Unix workstations. KDE has developed a high
quality development framework for Unix, which allows for the rapid and
efficient creation of applications.
GNOME is based on the GTK+ toolkit.
And a quote from the GNOME home page:
GNOME stands for GNU Network Object Model Environment. The GNOME project
intends to build a complete, user-friendly desktop based entirely on free
software. GNOME is part of the GNU project, and GNOME is part of the Open
Source(tm) movement. The desktop will consist of small utilities and larger
applications which share a consistent look and feel. GNOME uses GTK+ as the
GUI toolkit for all GNOME-compliant applications.
XFce is a lighter weight, less featureful Desktop
Environment that does not get as much attention as the others.
XFce is also based on the GTK+ toolkit. And a
quote from the XFce home page:
The XFce project was first started because I needed a simple, light and
efficient environment for my Linux System.
I believe that the desktop environment should be made to increase user
productivity. Therefore, the goal is keep most system resources for the
applications, and not to consume all memory and CPU usage with the desktop
environment.
All these have their own extensive documentation. If you can't find what you
need installed on your system, check the respective home pages.
X and the Command Line What would a Unix-like operating system be without a command line
interface? The command line can be useful, and is readily available with
X. In fact, for many it is an integral part
of their X working environment.
Any X program can be started directly from the
command line just by typing the program name at a shell prompt in an
xterm, or other terminal window. Most applications will
have a very rich set of command line options, such as
background color, font, geometry (screen placement), etc, etc. Command line
options over-ride compiled in defaults, or other system enabled
resources.
Many traditional X programs will use the same
basic names for command line options. All applications written using the
MIT X Toolkit Intrinsics (Xt) (such as those included with XFree86)
automatically accept the following options. Some non-Xt applications also use
these, or something similar. For instance, geometry is close
to a universally accepted option.-display [host]:display[.screen] This option specifies the X server display to use. This is often used
where applications are run on one system, and displayed on another. The
application needs to know where to display. This
is sometimes also accomplished by setting the $DISPLAY
variable, which uses the same syntax.
-geometry geometry The initial size and location of the window, in a format such as
width x height +horz_offset +vert_offset or
+horz_offset -vert_offset. Note that if you put in a
negative horizontal or vertical offset, the window will be placed counting
backward from the right or the bottom of the screen, respectively, instead
of from the top left corner.
-font fontname The font to use for displaying the text in your window (see font section
below).
-bg color The color to use for the window background. Typically this is a
color name (see below).
-fg color The color to use for the window foreground (i.e. fonts, etc).
-name resource-name Useful for specifying the name under which the resources for this
application will be found (e.g. as specified in
.Xdefaults). This is useful to distinguish between
invocations of the same application. For example, two
xterms can be named differently so that
they may inherit different resources based upon the specified names in
the resource database.
-title string This is the title to be used for the window on your display, generally used
by the Window Manager to put a descriptive title at the top of the window.
Not to be confused with the -name option.
-iconic Open window in an iconified state.
-xrm resource-string This option specifies a resource name and value to override any defaults
that may already be set (i.e. via .Xresources or
similar). Also useful for setting X resources
that do not have explicit command line options. For example, the command
line xterm -xrm xterm*background: blue ent is
functionally the same as xterm -bg blue ent.
These are the most noteworthy. There are others. Many programs will have
their own additional options that are application specific. Many newer
applications today don't necessarily adhere to the Xt standards, and will use
their own options, or those provided by their respective toolkit.
If nothing else, man pages are a good reference for command syntax, and are
your friends here. Or, the application will have a --usage or
--help command line switch to list available options:
$ gnome-terminal --usage
Usage: gnome-terminal [-?] [--disable-sound] [--enable-sound]
[--espeaker=HOSTNAME:PORT] [--version] [--usage] [--gdk-debug=FLAGS]
[--gdk-no-debug=FLAGS] [--display=DISPLAY] [--sync] [--no-xshm]
[--name=NAME] [--class=CLASS] [--gxid_host=HOST] [--gxid_port=PORT]
[--xim-preedit=STYLE] [--xim-status=STYLE] [--gtk-debug=FLAGS]
[--gtk-no-debug=FLAGS] [--g-fatal-warnings] [--gtk-module=MODULE]
[--disable-crash-dialog] [--sm-client-id=ID] [--sm-config-prefix=PREFIX]
[--sm-disable] [--tclass=TCLASS] [--font=FONT] [--nologin] [--login]
[--geometry=GEOMETRY] [-e COMMAND] [-x COMMAND] [--foreground=COLOR]
[--background=COLOR] [--solid] [--pixmap=PIXMAP] [--bgscroll]
[--bgnoscroll] [--shaded] [--noshaded] [--transparent] [--utmp]
[--noutmp] [--wtmp] [--nowtmp] [--lastlog] [--nolastlog] [-t TITLE]
[--icon=ICON] [--termname=TERMNAME] [--start-factory-server]
[--use-factory]
xterm and friends Sooner or later, most of us need to access the command line
for one reason or another. For some, this might even be a common way of
working in X. In addition to being able to launch
X applications from the command prompt, there
is also a wealth of programs that run in text mode for
Linux.
This is possible via terminal emulators such as
xterm. The closest counterpart from Microsoft is the
so-called DOS-box, which is child's play by comparison. Linux terminals support
color, full mouse copy/paste (and some wheeled mice), pseudo-transparency and
pixmap backgrounds, scrollbars, menus and generally a slew of other
features. While xterm is the best known such terminal
emulator, there are many similar programs. To name a few:
Eterm, rxvt,
aterm, konsole
(KDE) and gnome-terminal.
In typical usage, when a terminal emulator window is opened, a shell is
started for the user to interact with. The default for essentially all
Linuxes, is the bash shell. So when all is said
and done, the user is interacting with X, the
terminal, and the shell all at once. Each may have it's own influence. For
example, how keystrokes are handled since they move from hardware to X
server to terminal to the shell and finally echoed back to the user.
Quick and easy terminal configuration is done via the $TERM
variable, which is typically set in one of the user's shell configuration
files. Or the terminal itself will have a compiled in default. The default
value for this is most often xterm:
$ echo $TERM
xterm
Normally this is sufficient, as your vendor has already set this up in a
reasonable way. The $TERM variable is actually a reference to
an entry in the termcap database (man termcap), which is
typically installed as /etc/termcap. Unless you are
doing something really unusual, you probably won't need to change this.
Some additional terminal configuration can be done with the
stty command (see man page). Terminal configuration is
really beyond the scope of this document.
The terminal application itself (e.g. xterm) will also
have various configuration options. Permanent settings are best stored in
a ~/.Xdefaults or similar file for those applications
that support this. Generally speaking, applications with a GUI configuration
(such as gnome-terminal), will be configured by their own
menu driven configuration instead.
Also, you are interacting with the shell too, which can have it's own impact,
particularly on how keystrokes are handled at the shell prompt. For
bash, this can be adjusted in
~/.inputrc. Again, this is beyond the scope of this
document, but check with either local or on-line
bash (or other shell) references.
Terminal emulators like xterm require a monospaced font.
So forget about TrueType or Type 1 fonts.
<application moreinfo="none">X</application> Networking and Security As mentioned, X is essentially a networking
protocol with graphical displaying capabilities. This makes for some
interesting usage possibilities. And also means there are inherent security
considerations, as there is with any networking environment. And if you ever
connect to the Internet, you are in the midst of one very large, hostile
network ;-)
X clients connect to X servers via various networking protocols, including
TCP/IP. Even with just local connections. Possible usages here are to run an
application on one computer, and display it on another. Or, to actually log
in to a remote system, and have it display to your local screen, with the
client apps using the remote system's CPU and RAM.
Without any precautions, this can leave you wide open to various types of
mischief and abuse. For instance, anyone logged into to your system can
access your display, meaning they can see what you are doing
if they want to. Thankfully, most recent Linux releases come with some
default security precautions enabled. But it is best to make sure for
yourself that you are protected.
Both X networking and security are nicely covered
in The Remote X Apps Mini HOWTO, http://www.linuxdoc.org/HOWTO/mini/Remote-X-Apps.html,
so we won't need to try to rehash it here. Recommended reading. See other
references in the Links section of the
Appendix below.
A few recommended precautions:
Never, ever run X as root. The number of bad
things that can happen, dramatically increases when logged in as root.
Learn to run as much as possible as a regular user, and su to root only
when needed. This may sound like a lot of extra work (and probably is at
first), but once the right way of doing things is learned,
it soon becomes second nature.
A brief anecdote from a friend: he had a client who's new system stopped
working. Curiously, he found the entire
/dev directory was missing, which he re-installed and
all was well again. He was back a few days later and found the system
logged in as root to X, and someone had clicked
on /dev in the file manager, and dragged it onto the
desktop. Smooth move!
If you ever connect to a network with untrusted users, be sure to have a
firewall between you and them. This goes double for the Internet.
Firewalling is beyond the scope of this document, but is covered in many
other places, including your vendor's website. http://linuxdoc.org has several security
HOWTOs that can help as well. http://linuxsecurity.com/docs/
is another good place to look.
You can disable TCP connections with the -nolisten tcp
command line X server switch. This does not help for local connections
though. For xinit/startx:
exec X :0 -dpi 100 -nolisten tcp
Placed in ~/.xserverrc. And for xdm,
in /usr/lib/X11/xdm/Xservers:
:0 local /usr/X11R6/bin/X :0 -nolisten tcp
Performance Considerations As has been discussed, what we call X, is actually
a convergence of various components: X server, Window Manager, Desktop, etc.
With MS Windows, the GUI desktop is tightly integrated with the operating
system itself. This is not the case in Linux which follows the Unix tradition
of combining various independent components to achieve some end result. So we
have choices with each component and it's attendant configuration and
implementation. In short, much flexibility. This is where you come in. You
can try various possibilities and decide what you gives you the most bang for
the buck.
On low end hardware, this gives us much latitude to decrease the demand on
available system resources. This is good because, if given the opportunity,
X can be quite greedy with system resources. If
you've recently installed a new Linux distribution, you've probably been
given a default Desktop with many bells and whistles. And something
that will probably need a fair amount of memory and CPU to achieve a
reasonable level of performance. If you have the horse power, this should not
be a problem.
It is often said that Linux functions very well with relatively little
memory. This is true to a point. It does not mean though that every possible
configuration will run with low memory. So if you want to use memory hungry
applications, then you will have to have the memory. Or you will have to make
sacrifices to achieve a satisfactory level of performance. It is quite
possible to run X with reasonable performance on
16 Meg of RAM, and even less if you really want to push it. But you would
have to live with some real limitations.
Let's look at some of the components and ways to decrease the demand on
system resources, in case you are at the low end on hardware, or performance
is not up to expectations.Hardware No big surprise, but overall system performance will be best with a fast
graphics card, a fast hard drive, and lots and lots of memory -- if you want
both a fast and flashy system.
Graphics cards are of course necessary, and the X server's video performance
is tied to the card's chipset, and the corresponding XFree86 driver. Just
because a given card is supported by XFree86 does not necessarily mean it is
as well optimized as other cards! It may also perform better at a lower color
depth (see below). It may well be worth the trip to xfree86.org to see if
there are any notes related to your card with respect to performance or other
issues.
And you might try other versions of XFree86. At this time v4.2 was just
recently released. Some cards may still perform better with 3.3.6 due to the
way v4.x is being incrementally developed. If you are using x4.x and
performance is not good, then make sure you are using the latest available
version.
Memory The more memory, the better. X will do a lot
caching to help performance. But caching requires memory, and if there isn't
much to start with, then we would need to reduce memory requirements. Some
tips for those with low memory or performance problems: Use the free command to make sure all memory and swap is
recognized.
Make sure you don't have other system services that are hogging memory or
CPU. Use top or ps to see what is
running, and disable anything you can to free up memory and CPU. Again, a
default installation may have many things running that you don't really
need.
Make sure you have plenty of swap space. With low, or even modest, memory,
swap is all the more important. A general rule of thumb is twice as much swap
as physical memory. With low memory, this is not enough. Try four times real
memory. Or more. If you can't create more swap partitions, see the
mkswap man page about creating swap files instead.
Constant disk churning is a symptom of insufficient swap space, and the
system will be slowed as a result, sometimes drastically. Or, possibly this
may be the symptom of a poorly behaved kernel VM system (try another kernel
in this case).
Drive performance is important for swap performance. Make sure your drive has
DMA enabled if the drive supports it, and is otherwise tuned and performing
up to snuff. See the hdparm man page. Slow drive + slow
card + low memory = slow system.
Don't use KDE or GNOME
if memory is tight. These both require substantial memory, and are not
required to just run X. Think of these as
usability enhancements. 32M probably may not be enough. 64M may be decent,
depending on what other applications are being used, and other variables. 128M
should be adequate in most situations. 256M or more to
be comfortable. File Managers like Nautilus and
gmc can also be memory hungry.
Use a lightweight window manger. WindowMaker,
BlackBox, IceWM,
fvwm (and variants),
XFce, all have reputations of performing well with
low memory. There are surely others as well. Experiment.
fvwm is generally considered the lightest of the
light. A very nice desktop is still very possible even without
KDE or GNOME. In fact,
most KDE and GNOME
applications can still be used even if KDE and
GNOME are not running themselves (assuming the
right libs are installed).
Don't use fancy themes or backgrounds. Plain and simple is easier on
resources. Use a solid color background. Avoid pixmaps or gradients for any
kind of background, including menus, title bars, etc.
Use a lesser screen size and color depth. 800x600x16 will not push
X as hard and be easier on system resources than
higher values. While a ColorDepth of 24 is preferred, you probably will not
notice the difference of 16 with the majority of applications.
Some applications require much more memory than others. Some notable hogs are
Netscape, Mozilla, office suites, and
the Gimp. Netscape is faster than
Mozilla (but not as nice).
Netscape-Navigator uses less memory than
Netscape-Communicator. Close any of these apps when not in
use. Use text browsers like lynx or w3m
wherever you can, like reading locally installed HTML documentation. Much
faster, and much less memory is required.
Also, use text based clients for mail (mutt or
pine) and news (slrn or
trn). Again, faster and much less memory is used,
and these are after all text based protocols at heart anyway.
rxvt uses less memory than xterm,
konsole or gnome-terminal.
If you run an X session for long periods of time
(like days or weeks), restart X occasionally to
free memory tied up as cache.
Disable backing store and save-unders to
reduce memory usage (performance penalty though). Check
your Window Manager's settings too. See what modules are being loaded
in the Modules section of XF86Config as
well. Your installation may have many unnecessary ones enabled, or ones you
can't take advantage of (e.g. v4l, aka
Video4Linux).
Font servers may provide a slight performance boost by off-loading font
rendering to the font server, while freeing the X server to do other things.
But, the font server will use a small additional amount of memory as well.
So, you can try it either way to see if it makes a difference.
Lastly, RAM is cheap now. Buy some ;-) A new drive too.
RAM is still just too low for X? Check out
tinyX:
http://www.superant.com/smalllinux/tinyX01.html.
Reportedly runs in as little as 4 Meg of RAM.
X over the Network X is not particularly network friendly. In other words, it is a bandwidth
hog. This should not be a problem in LAN situations, but may be if trying to
use X over the Internet.lbxproxy, the low bandwidth X proxy, utilizes
various optimizations to improve performance in low bandwidth, or
high latency situations. See the man page.
VNC (Virtual Network Computing), has some of the same advantages as
X for displaying applications on remote systems, but is more network
friendly. Your Linux installation should have both VNC client and server
packages available.
Other Tips Other tips to eek out better performance: Use xset to speed up the keyboard. This can make the
system feel more responsive even if it isn't really. The default always
seemed sluggish to me.
reniceX to give it a higher
priority. Other platforms give the GUI high scheduling priority to achieve
better responsiveness. But this is at a cost to other processes. Linux is a
blank slate. You might include the font server (if being used), and key
KDE and GNOME processes
as well.
nice -n -10 X :0
This won't do much on systems that are mostly idle.
This does not work so well with startx since
X runs as root, and you're not root, right? So
you'd have to use something like sudo to have this done
automatically.
AppendixTerminology and Usage There are a few basic concepts and terminologies you should be familiar with.
These terms will appear here, in the manual pages, and in other help files and
documentation.
The X server is the low-level driver software that interacts
with your video card and other system hardware, and manages the
display and the various components attached to the
display (keyboard, mouse, etc.). And, of course, handles
requests from clients as well. There are different X servers for different
chipsets.
X Servers are referenced in the form of:
host.domain:display_number.screen_number An example would look like: my_computer:0.0 If host (and domain) is omitted, localhost is assumed. Host
can be a remote host. If screen is omitted, then
0 (the first screen) is assumed. In it's shortest form, the
X server is often represented as just :0, which would be the
first local display. X supports
multiple displaysand multiple
screens.
Screen and Display have special meanings in
relation to X servers, in addition to their more common usage.
When X is invoked, the X server will initialize
one or more displays. Yes, X can
have more than one display available (though this is not a
common configuration for the average user). Each display is
a separate instance of X. The display
includes not only the obvious video components, but also the keyboard,
mouse and other input type components. The user can only access one
display at a time via the same keyboard and
monitor. Displays may reside locally, or on a networked
host somewhere, or both. It is possible that if multiple
displays are available, the user can choose which one he
wants when he logs in. Each display may have its own
unique configuration (e.g. resolution). But again, the most typical
configuration is just one display with one screen,
which is how most of us use X.
In reference to X servers, screen means the primary video
output with which you view X.
And there can be more than one screen, just like you can
have more than one display. Additional
screens are used in multi-headed displays for
instance. In fact you can even have more than one computer running off a
single X server. This is beyond the scope of this document, but you should
be aware of this degree of flexibility as it is an important ingredient of
the X protocol.
Desktop can mean different things in different
contexts. Often, desktop means what is more properly
called the Desktop Environment. Prime examples of this are
KDE, GNOME, and the not
as well-known CDE, which are high level
applications that control much of how the user interacts with the
X session. They provide consistent look and
feel, as well as consistent configuration and come bundled with their own
set of utilities for common tasks.
Desktop also sometimes just means the viewable screen area.
This is more of the MS Window's meaning. X
environments though are capable of having multiple virtual
desktops that can be switched between as needed. This helps with
organizing different tasks. Each desktop may its own windows
and clients that are specific to it. Right now I have seven
WindowMaker desktops
(WindowMaker calls them
WorkSpaces), and one of those I have dedicated to writing
this document. This desktop has thirteen unique windows at
the moment (man pages, browser windows, clock, gvim, xterms, etc).
Clients are any program that connect to the X server, and
require an X server for some task (e.g. to display itself). Often, these
are displayed in their own window, but not always. For
instance, if I use CTRL-N to open a new
Mozilla window, this is one
X client but with two windows. If I run a command
line X utility like xev to
view key and mouse events, this runs in the xterm's
window, so has none of its own, but is still a client.
Clients can be locally running applications, or applications that are
running on another system over the network, but are displayed locally.
The Window Manager is a special type of client application
and a user definable component of the GUI. It is what the user interacts
with to a large extent. The Window Manager provides such functionality as
window borders and decorations, menus, icons, virtual desktops, button
bars, tool bars, and allows the user to customize these. It is technically
possible to run X without a window manager
(though not very functional), but not the other way around. Window managers
should not be confused with Desktop Environments like
KDE. Desktop Environments include their own
preferred Window Manager, but this is a configurable. There is some
overlapping of responsibilities between Window Managers and Desktop
Environments.
The root window is the background of your screen. It is
referred to as a window in name alone, it does not behave like any other
window, but rather you run your applications on the root window, or put an
image on it, or perhaps just a solid color. All other windows are children
of this parent window. The root window conceivably can be larger than the viewable
screen area.
The pointer is the arrow or indicator of any
given shape which represents the location of your mouse, or other pointing
device. The pointer often changes to give you contextual feedback as to
what will happen when you use the mouse at that point on the screen.
The window is a frame in which any given application runs
and which is managed by the Window Manager. This includes
pretty much anything except the so-called root window. Even windows which
do not appear to have frames, titles, or normal borders of any kind are
being managed by your window manger. The active window is
the window you are currently using. This window will will respond to the
keyboard when you type, and is traditionally denoted by the fact that your
mouse cursor is pointing at it, though this is not always the case. The
active window is said to have focus. Most Window Managers
will somehow highlight the active, or focused, window to
differentiate it from other windows.
Menus, icons and task bars
behave in X similar to the way they behave in
other windowing systems, and the same general principles apply.
Windows that run text only applications are called terminal
emulators, such as xterm and various
similar applications. This is the well-known command line in
an X environment. These basically emulate a console text-only display, and
have some advantages due to their being used in
X. These are much more complex and sophisticated
applications than a simple DOS box on Windows.
Widgets is the term used to describe such GUI control
components as buttons, sliders, menus, scrollbars, listboxes, checkboxes, etc.
Toolkits are libraries containing a diverse set of widgets
with the same look and feel. Some common examples are
GTK+ (used by GNOME,
Mozilla and others), Xaw
(X Athena Widget set), Tk,
Motif and QT (used
by KDE). Applications are built with one toolkit
or another. Sometimes the same application can be built with different
toolkits, depending on compile time options.
Window geometry is a shorthand way of expressing a window's
size and screen placement. This might look like
60x20+10+50, which is WIDTH x HEIGHT +VERT_OFFSET
+HORZ_OFFSET. While both pairs are often specified, it is
permissible to use just one or the other pair.
In X lingo, resources are
definable application attributes. Commonly available
resources are fonts, colors, size, window title, etc,
etc.
Links and other References The definitive source of information on XFree86 is, of course,
http://xfree86.org. Don't forget
the man pages that you have installed already too (X, Xserver, XF86Config,
XFree86, xdm, xinit, xmodmap, startx, xauth, Xsecurity, etc, etc). These are
really mostly decent, though some are quite technical.
Some pages at xfree86.org to check:
Docs and support info: http://www.xfree86.org/support.html for
various versions and topics.
README: http://www.xfree86.org/current/README.html Release Notes: http://www.xfree86.org/current/RELNOTES.html DRI: http://www.xfree86.org/current/DRI.html Status: http://www.xfree86.org/current/Status.html Mouse: http://www.xfree86.org/current/mouse.html Supported card list:
http://xfree86.org/cardlist.html Other related documents from LDP:
If you are just starting out, you may find the
X Window System Architecture Overview HOWTO, http://www.linuxdoc.org/HOWTO/XWindow-Overview-HOWTO/
to be helpful. It covers all the basic concepts quite well.
The Remote X Apps Mini HOWTO,
http://www.linuxdoc.org/HOWTO/mini/Remote-X-Apps.html,
does a nice job of discussing running X
remotely, and related security issues of X networking.
The XDMCP HOWTO,
http://www.linuxdoc.org/HOWTO/XDMCP-HOWTO/index.html,
covers the X Display Manager Control Protocol, for running
X remotely. Also,
The XDM and X Terminal mini-HOWTO,
http://www.linuxdoc.org/HOWTO/mini/XDM-Xterm/index.html.
The XFree86 HOWTO,
http://www.linuxdoc.org/HOWTO/XFree86-HOWTO/index.html,
succinctly covers installation, and initial configuration.
The XFree86 Video Timings HOWTO,
http://www.linuxdoc.org/HOWTO/XFree86-Video-Timings-HOWTO/index.html,
gets down and dirty with the finer points of monitor tuning. Generally
not required for XFree86 v4.x.
The Xinerama HOWTO,
http://www.linuxdoc.org/HOWTO/Xinerama-HOWTO.html,
covers multi-headed displays.
The Font HOWTO,
,
covers various font topics.
The Font De-Uglification Mini HOWTO,
http://www.linuxdoc.org/HOWTO/mini/FDU/index.html,
covers a range of X font issues.
The International Keyboard HOWTO;
http://www.linuxdoc.org/HOWTO/mini/Intkeyb/index.htmlThe Linux Infrared HOWTO:
http://www.linuxdoc.org/HOWTO/Infrared-HOWTO/index.html Looking for information on a Window Manager, or wanting to try
something new or different:
http://www.plig.org/xwinman/ Wheel mice tips and configuration:
http://koala.ilog.fr/colas/mouse-wheel-scroll/ Linux and Laptops:
http://www.linux-laptop.net/ The O'Reilly series on X Window! Visit http://www.ora.com/ for the definitive books on X.
The X Consortium's web site is http://www.x.org/ ... or perhaps it's moved to
http://www.opengroup.org/.
http://www.x11.org/ is sort of a clearinghouse
for all things X.
And for everything else under the Sun: http://google.com/linux/.
An incredible resource in its own right.