X Windows

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The X Windows System (also known as X11, X, and X-Windows) is a windowing system, common on Linux and Unix-like operating systems. X provides the basic framework for a windowed GUI environment. Drawing and moving windows on the display as well as interaction with the keyboard and mouse are handled by X. Many EMAC machines use an X server to provide the graphical user interface; others use a framebuffer. To determine which type is used on a specific machine, consult the machine's documentation.

Utilities

The following list is a collection of common X utilities included on Standard EMAC OE builds.

• xdpyinfo

  xdpyinfo is a utility for displaying information about the X server. This utility may not work unless it is run from a graphical terminal within the X server session.

• xinit

  xinit is the low-level utility that is used to start the X server.

• startx

  startx is the high level utility for starting X. It starts X with the configured desktop manager.

• /etc/init.d/xserver-nodm

  /etc/init.d/xserver-nodm is the init script found on EMAC OE Linux systems which have an X server. This is normally the correct script to use for starting and stopping the X server. When passed start as the only argument, this script will launch the X server, output log information about the startup process, then return the user to the shell (by forking the launcher into a daemon). Pass stop to this script to shut down the X server properly.

• xkbcomp

  xkbcomp is a keymap compiler that is most commonly used to create a .xkm keymap file to be read by X servers or utilities.

• xmodmap

  xmodmap is a utility that is used for modifying keymaps.

• xrandr

  xrandr is used to set the size, orientation and/or reflection of the outputs for a screen.

• xscreensaver

  The xscreensaver program waits until the keyboard and mouse have been idle for a period, and then runs a graphics demo chosen at random.

• xset

  xset is used to set various user preference options of the display.

• xterm

  The xterm program is a terminal emulator for the X Window System.

• xtscal

  xtscal calibrates the touchscreen on an X system.

• xinput

  xinput is a utility to list available input devices, query information about a device and change input device settings.

Please refer to the man pages for each command to get specific instructions and options:

developer@ldc:~# man <command>

SSH X Forwarding

While using SSH to access a system running the X Windows System, it is possible to have any windows attached to a program running on the remote system appear on the local machine. To connect to the system at the IP address 10.0.2.41 with X forwarding, enter the following command:

developer@ldc:~# ssh -X user@10.0.2.41

Other than the -X option, the procedure for logging in is the same as that listed on the System Login Page.

To verify that X forwarding is enabled, the following command may be entered:

user@emac-oe:~# xclock &

This will open a small analog clock in a window on the host machine. The window can be closed after verifying the correct functionality.

Alternatively, the xclock program can be run with X forwarding with one ssh command:

user@ldc:~# ssh -X user@10.0.2.41 "xclock"

Links

The following are links to detailed documentation relating to the X Windows System.

General

• www.x.org

• Getting Started

• X Window System Administrator's Guide

• X11R6.9 User Documentation

• X11R7.7 User Documentation

• Keith Packard Talks

• X11 Config for Ubuntu

Toolkits

• GTK+

• Qt

• XCB

X Development

• Development

• New Developer Guide

• Xlib Manual

• Qt for X11

See Also

Framebuffer