Linux Commands Examples

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primitive command line interface to RandR extension

see also : cvt - xkeystone


xrandr [-help] [-display display] [-q] [-v] [--verbose] [--dryrun] [--screen snum] [--q1] [--q12] [--current] [--noprimary] [--panning widthxheight[+x+y[/track_widthxtrack_height+track_x+track_y[/border_left/border_top/border_right/border_bottom]]]] [--scale xxy] [--scale-from wxh] [--transform a,b,c,d,e,f,g,h,i] [--primary] [--prop] [--fb widthxheight] [--fbmm widthxheight] [--dpi dpi] [--newmode name mode] [--rmmode name] [--addmode output name] [--delmode output name] [--output output] [--auto] [--mode mode] [--preferred] [--pos xxy] [--rate rate] [--reflect reflection] [--rotate orientation] [--left-of output] [--right-of output] [--above output] [--below output] [--same-as output] [--set property value] [--off] [--crtc crtc] [--gamma red:green:blue] [--brightness brightness] [-o orientation] [-s size] [-r rate] [-x] [-y]

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xrandr --output VGA1 --off
xrandr --orientation normal
xrandr --output LVDS --auto
xrandr --output VGA-0 --off
xrandr -o normal

How to change virtual screen resolution on Ubuntu (connecting via VNC without real display connected)?

You could consider changing the resolution on the VNC server? I'm not sure of your setup but if the VNC server is on the virtualized machine you could check the vncserver instantiation point and change the -geometry flag there?

Alternatively, I would look at xorg.conf and add the mode you are looking for, since xrandr is saying its not availiable. This article covers the basics of xorg.conf editing


Setting primary monitor in ubuntu without xrandr

If i'm not wrong xrandr only changes settings on the fly, so if you want to make them permanentely you have to store them using other method.

The easiest way in Gnome is editing ~/.config/monitors.xml. There you can set up which monitor is the primary. Example:

<monitors version="1">
      <output name="LVDS1">
          /* (...) */
      <output name="VGA1">
      <output name="HDMI1">
          /* (...) */
      <output name="DP1">

This works in Ubuntu (Gnome/Unity), but I have never used Kubuntu so it may use a different location, or even use other file. Also, this will only be applied after you login.

If that doesn't work, you will have to edit xorg.conf. I can't help you much in that, but in a quick search I found this post which should help. Also check out this Ubuntu Wiki page.

Hope this helps.


Sets an output called LVDS to its preferred mode, and on its right put an output called VGA to preferred mode of a screen which has been physically rotated clockwise:

xrandr --output LVDS --auto --rotate normal --pos 0x0 --output VGA --auto --rotate left --right-of LVDS

Forces to use a 1024x768 mode on an output called VGA:

xrandr --newmode "1024x768" 63.50 1024 1072 1176 1328 768 771 775 798 -hsync +vsync
xrandr --addmode VGA 1024x768
xrandr --output VGA --mode 1024x768

Enables panning on a 1600x768 desktop while displaying 1024x768 mode on an output called VGA:

xrandr --fb 1600x768 --output VGA --mode 1024x768 --panning 1600x0

Have one small 1280x800 LVDS screen showing a small version of a huge 3200x2000 desktop, and have a big VGA screen display the surrounding of the mouse at normal size.

xrandr --fb 3200x2000 --output LVDS --scale 2.5x2.5 --output VGA --pos 0x0 --panning 3200x2000+0+0/3200x2000+0+0/64/64/64/64

Displays the VGA output in trapezoid shape so that it is keystone corrected when the projector is slightly above the screen:

xrandr --fb 1024x768 --output VGA --transform 1.24,0.16,-124,0,1.24,0,0,0.000316,1

xrandr --orientation inverted
$ xrandr -q
xrandr --output VGA-0 --off

How do I align the bottom edges of two monitors with xrandr?

Someone managed ... hope this helps?

Dual Screens with aligned bottom edges


Triple monitor setup in linux

So here is my working xorg.conf for a three monitor setup. It's setup as two screens, which I didn't originally like, but I'm not pretty happy with. It allows me to run the two lcds like a normal dual monitor setup, and still display movies and stuff on my projector, all from the same computer. It's also nice that I can work on the dual-monitor setup, without having to turn on the projector because a window occasionally starts up on that screen, like I would if they were all the same xscreen.

Technically, I could run a fourth monitor! I think I'm more likely to invest in a new cpu and motherboard before I try that, though. It depends on how soon Starcraft 2 comes out.

# nvidia-settings: X configuration file generated by nvidia-settings
# nvidia-settings:  version 1.0  (buildd@crested)  Sun Feb  1 20:25:37 UTC 2009
# edited by me (brendan) 2010-04-18

#   NVIDIA magic (something about glx-new?)
Section "Module"
    Load           "glx"

Section "Extensions"
    Option         "Composite" "Enable"

#   Keyboards and Mice
Section "InputDevice"
    # generated from default
    Identifier     "Keyboard0"
    Driver         "kbd"

Section "InputDevice"
    # generated from default
    Identifier     "Mouse0"
    Driver         "mouse"
    Option         "Protocol" "auto"
    Option         "Device" "/dev/psaux"
    Option         "Emulate3Buttons" "no"
    Option         "ZAxisMapping" "4 5"

#   Physical Monitors:
Section "Monitor"
    Identifier     "Monitor0"
    VendorName     "Acer"
    ModelName      "Acer H233H"
    HorizSync       40.0 - 70.0
    VertRefresh     60.0

Section "Monitor"
    Identifier      "Monitor1"
    VendorName     "Acer"
    ModelName      "Acer AL2216W"
    HorizSync       40.0 - 70.0
    VertRefresh     60.0

Section "Monitor"
    Identifier     "Monitor2"
    VendorName     "BenQ"
    ModelName      "BenQ W500"
    HorizSync       44.955 - 45.0
    VertRefresh     59.94 - 60.0

#   Physical Video Cards/Ports:
Section "Device"
    Identifier     "Device0"
    Driver         "nvidia"
    VendorName     "NVIDIA Corporation"
    BoardName      "GeForce 9800 GTX+"
#    Screen          0
    BusID          "PCI:5:0:0"

Section "Device"
    Identifier    "Device2"
    Driver        "nvidia"
    VendorName    "nVidia Corporation"
    BoardName     "GeForce 7900 GT/GTO"
    BusID         "PCI:4:0:0"
    Option        "TVStandard" "HD720p"

####    Default 3-monitor Layout 'default'

Section "ServerLayout"
    Identifier     "Default Layout"
    Screen      0  "Screen0" 0 0
    Screen      1  "Screen2" LeftOf "Screen0"
    InputDevice    "Keyboard0" "CoreKeyboard"
    InputDevice    "Mouse0" "CorePointer"

Section "ServerFlags"
    Option         "Xinerama" "0"

#   Virtual Screens
Section "Screen"
    Identifier     "Screen0"
    Device         "Device0"
    Monitor        "Monitor0"
    DefaultDepth    24
    Option         "TwinView" "1"
#    Option         "NoTwinViewXineramaInfo"
    Option         "metamodes" "DFP-0: 1920x1080 +1680+0, DFP-1: 1680x1050 +0+30"
    SubSection     "Display"
        Depth       24

Section "Screen"
    Identifier     "Screen2"
    Device         "Device2"
    Monitor        "Monitor2"
    DefaultDepth    24
    Option         "TwinView" "0"
    Option         "metamodes" "1280x720"
    SubSection     "Display"
        Depth       24

Error on changing the resolution of a vnc session in linux on the fly

I would guess, off the top of my head, that your version of VNC doesn't support RANDR. Are you sure it's supported?


Use xrandr to set the absolute position of the screen?

The --pos switch should allow you to set the position of an individual output (ie monitor) within the overall virtual screen.

So you probably want to use --pos 1920x56 or something on the output that drives the right hand monitor if I've understood the man page correctly.


xrandr changes X's orientation too slowly

Sorry, because of the way X and randr works, this is not possible.


Crop display size in linux

While it has a bit of overhead and gives reduced graphics performance, you could use Xnest to run another X server (with any resolution you want) in a window in your inital X server.

Then you can place this window in the desired part of the screen, or (since it's the right hand side that's broken) just run bare Xorg without a window manager to have it placed in the top right with no window decorations.


In gnome, how can I configure the definition of "full screen" to make large VNC windows behave nicely on a dual screen setup?

You need to turn off Xinerama. This is done in the /etc/xorg.conf file. This may also kill your ability to do dual head though. If you're running on NVIDIA setup a proper xorg.conf with the 'nvidia-settings' program and you won't need Xinerama.


Ubuntu xrandr rotate issue

Same problem on Linux Mint 11 Katya / Ubuntu 11.04. xrandr -o right doesn't work anymore, but unlike previous Ubuntu /Mint versions, the "Monitors" (or "Displays" dialog of Ubuntu/Mint allows the rotation. You still have to add Option "RandRRotation" "on" to xorg.conf, though.


Xrandr is used to set the size, orientation and/or reflection of the outputs for a screen. It can also set the screen size.

If invoked without any option, it will dump the state of the outputs, showing the existing modes for each of them, with a ’+’ after the preferred mode and a ’*’ after the current mode.

There are a few global options. Other options modify the last output that is specified in earlier parameters in the command line. Multiple outputs may be modified at the same time by passing multiple --output options followed immediately by their corresponding modifying options.


Print out a summary of the usage and exit.

-v, --version

Print out the RandR version reported by the X server and exit.


Causes xrandr to be more verbose. When used with -q (or without other options), xrandr will display more information about the server state. Please note that the gamma and brightness informations are only approximations of the complete color profile stored in the server. When used along with options that reconfigure the system, progress will be reported while executing the configuration changes.

-q, --query

When this option is present, or when no configuration changes are requested, xrandr will display the current state of the system.


Performs all the actions specified except that no changes are made.


Apply the modifications without grabbing the screen. It avoids to block other applications during the update but it might also cause some applications that detect screen resize to receive old values.

-d, -display name

This option selects the X display to use. Note this refers to the X screen abstraction, not the monitor (or output).

--screen snum

This option selects which screen to manipulate. Note this refers to the X screen abstraction, not the monitor (or output).


Forces the usage of the RandR version 1.1 protocol, even if a higher version is available.


Forces the usage of the RandR version 1.2 protocol, even if the display does not report it as supported or a higher version is available.

randr version 1 1 options

These options are available for X servers supporting RandR version 1.1 or older. They are still valid for newer X servers, but they don’t interact sensibly with version 1.2 options on the same command line.
-s, --size size-index or --size widthxheight

This sets the screen size, either matching by size or using the index into the list of available sizes.

-r, --rate, --refresh rate

This sets the refresh rate closest to the specified value.

-o, --orientation rotation

This specifies the orientation of the screen, and can be one of normal, inverted, left or right.


Reflect across the X axis.


Reflect across the Y axis.

randr version 1 2 options

These options are only available for X server supporting RandR version 1.2 or newer.
--prop, --properties

This option causes xrandr to display the contents of properties for each output. --verbose also enables --prop.

--fb widthxheight

Reconfigures the screen to the specified size. All configured monitors must fit within this size. When this option is not provided, xrandr computes the smallest screen size that will hold the set of configured outputs; this option provides a way to override that behaviour.

--fbmm widthxheight

Sets the reported values for the physical size of the screen. Normally, xrandr resets the reported physical size values to keep the DPI constant. This overrides that computation.

--dpi dpi

This also sets the reported physical size values of the screen, it uses the specified DPI value to compute an appropriate physical size using whatever pixel size will be set.

--newmode name mode

New modelines can be added to the server and then associated with outputs. This option does the former. The mode is specified using the ModeLine syntax for xorg.conf: clock hdisp hsyncstart hsyncend htotal vdisp vsyncstart vsyncend vtotal flags. flags can be zero or more of +HSync, -HSync, +VSync, -VSync, Interlace, DoubleScan, CSync, +CSync, -CSync. Several tools permit to compute the usual modeline from a height, width, and refresh rate, for instance you can use cvt.

--rmmode name

This removes a mode from the server if it is otherwise unused.

--addmode output name

Add a mode to the set of valid modes for an output.

--delmode output name

Remove a mode from the set of valid modes for an output.

Per-output options
--output output

Selects an output to reconfigure. Use either the name of the output or the XID.


For connected but disabled outputs, this will enable them using their preferred mode (or, something close to 96dpi if they have no preferred mode). For disconnected but enabled outputs, this will disable them.

--mode mode

This selects a mode. Use either the name or the XID for mode


This selects the same mode as --auto, but it doesn’t automatically enable or disable the output.

--pos xxy

Position the output within the screen using pixel coordinates. In case reflection or rotation is applied, the translation is applied after the effects.

--rate rate

This marks a preference for refresh rates close to the specified value, when multiple modes have the same name, this will select the one with the nearest refresh rate.

--reflect reflection

Reflection can be one of ’normal’ ’x’, ’y’ or ’xy’. This causes the output contents to be reflected across the specified axes.

--rotate rotation

Rotation can be one of ’normal’, ’left’, ’right’ or ’inverted’. This causes the output contents to be rotated in the specified direction. ’right’ specifies a clockwise rotation of the picture and ’left’ specifies a counter-clockwise rotation.

--left-of, --right-of, --above, --below, --same-as another-output

Use one of these options to position the output relative to the position of another output. This allows convenient tiling of outputs within the screen. The position is always computed relative to the new position of the other output, so it is not valid to say --output a --left-of b --output b --left-of a.

--set property value

Sets an output property. Integer properties may be specified as a valid (see --prop) decimal or hexadecimal (with a leading 0x) value. Atom properties may be set to any of the valid atoms (see --prop). String properties may be set to any value.


Disables the output.

--crtc crtc

Uses the specified crtc (either as an index in the list of CRTCs or XID). In normal usage, this option is not required as xrandr tries to make sensible choices about which crtc to use with each output. When that fails for some reason, this option can override the normal selection.

--gamma red:green:blue

Set the specified floating point values as gamma correction on the crtc currently attached to this output. Note that you cannot get two different values for cloned outputs (i.e.: which share the same crtc) and that switching an output to another crtc doesn’t change the crtc gamma corrections at all.

--brightness brightness

Multiply the gamma values on the crtc currently attached to the output to specified floating value. Useful for overly bright or overly dim outputs. However, this is a software only modification, if your hardware has support to actually change the brightness, you will probably prefer to use xbacklight.

randr version 1 3 options

Options for RandR 1.3 are used as a superset of the options for RandR 1.2.

Return the current screen configuration, without polling for hardware changes.


Don’t define a primary output.

Per-output options

This option sets the panning parameters. As soon as panning is enabled, the CRTC position can change with every pointer move. The first four parameters specify the total panning area, the next four the pointer tracking area (which defaults to the same area). The last four parameters specify the border and default to 0. A width or height set to zero disables panning on the according axis. You typically have to set the screen size with --fb simultaneously.

--transform a,b,c,d,e,f,g,h,i

Specifies a transformation matrix to apply on the output. Automatically a bilinear filter is selected. The mathematical form corresponds to:

a b c
d e f
g h i

The transformation is based on homogeneous coordinates. The matrix multiplied by the coordinate vector of a pixel of the output gives the transformed coordinate vector of a pixel in the graphic buffer. More precisely, the vector (x y) of the output pixel is extended to 3 values (x y w), with 1 as the w coordinate and multiplied against the matrix. The final device coordinates of the pixel are then calculated with the so-called homogenic division by the transformed w coordinate. In other words, the device coordinates (x’ y’) of the transformed pixel are:

x’ = (ax + by + c) / w’ and
y’ = (dx + ey + f) / w’ ,
with w’ = (gx + hy + i) .

Typically, a and e corresponds to the scaling on the X and Y axes, c and f corresponds to the translation on those axes, and g, h, and i are respectively 0, 0 and 1. The matrix can also be used to express more complex transformations such as keystone correction, or rotation. For a rotation of an angle T, this formula can be used:

cos T -sin T 0
sin T cos T 0
0 0 1

As a special argument, instead of passing a matrix, one can pass the string none, in which case the default values are used (a unit matrix without filter).

--scale xxy

Changes the dimensions of the output picture. Values superior to 1 will lead to a compressed screen (screen dimension bigger than the dimension of the output mode), and values below 1 leads to a zoom in on the output. This option is actually a shortcut version of the --transform option.

--scale-from wxh

Specifies the size in pixels of the area of the framebuffer to be displayed on this output. This option is actually a shortcut version of the --transform option.


Set the output as primary. It will be sorted first in Xinerama and RANDR geometry requests.

see also

Xrandr, cvt , xkeystone , xbacklight


Keith Packard, Open Source Technology Center, Intel Corporation. and Jim Gettys, Cambridge Research Laboratory, HP Labs, HP.

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