xwud

xwud [-options ...] [file]

-geometry <geometry string>
    Specifies the preferred size and position of the window where the image will be displayed. E.g., 100x50+10+20.

-display <display name>
    Specifies the X server to connect to. E.g., :0.0 or hostname:0.

-inverse
    Displays the image in inverse colors (reverse video, swapping black and white, etc.).

-mono
    Forces the image to be displayed in monochrome (black and white), regardless of its original color depth.

-gray
    Forces the image to be displayed in grayscale.

-std
    Uses the default (standard) visual type for display on the X server.

-best
    Attempts to use the 'best' available visual type that closely matches the characteristics of the image data.

-<visual id>
    Specifies a particular hexadecimal visual ID to use for display. This can be found using xdpyinfo.

-name <name>
    Assigns a specific name to the created window. This name can be used by window managers or other X tools.

-notitle
    Instructs the window manager not to add a title bar or borders to the xwud window.

-help
    Prints a usage message detailing the available command-line options and then exits.

xwud (X Window Undump) is a utility provided with the X Window System that allows users to display images created by the xwd (X Window Dump) command. These xwd files are essentially screenshots or 'dumps' of an X window's contents. xwud reads these window dump files, either from a specified file path or from standard input, and renders them onto an X display.

It is particularly useful for viewing and verifying the output of xwd or for simple image display within an X environment. The command supports various visual types, automatically adapting to the visual type of the image being displayed, or allowing the user to specify a preferred visual. It's a basic but fundamental tool for handling X window dumps within the X.Org ecosystem.

xwud is a command-line utility specifically designed for the X Window System; it cannot be used in a text-only console environment. Its input is strictly limited to xwd format files, and it offers no image editing capabilities or advanced viewing features. It serves primarily as a basic viewer for its specific file type.

xwud terminates automatically if its display window is closed or destroyed by the user (e.g., clicking the close button) or by the window manager.

If no file argument is provided on the command line, xwud automatically reads the X window dump data from standard input. This allows it to be used effectively in pipes, such as xwd -root | xwud (to dump the root window and immediately display it).

xwud has been a fundamental utility within the X Window System since its early development. It was created as a companion tool to xwd, the X Window Dump utility, to provide a simple means of verifying and displaying the xwd format image files. Its design is straightforward, focusing solely on the task of 'undumping' these specific image files. As part of the X.Org distribution, it has maintained its core functionality with minimal changes over the decades, reflecting its specific and foundational role in X window management.

xwd(1), xdpyinfo(1)