| XREFRESH(1) | General Commands Manual | XREFRESH(1) | 
xrefresh - refresh all or part of an X screen
Xrefresh is a simple X program that causes all or part of your screen to
  be repainted. This is useful when system messages have messed up your screen.
  Xrefresh maps a window on top of the desired area of the screen and
  then immediately unmaps it, causing refresh events to be sent to all
  applications. By default, a window with no background is used, causing all
  applications to repaint ``smoothly.'' However, the various options can be used
  to indicate that a solid background (of any color) or the root window
  background should be used instead.
  - -white
- Use a white background. The screen just appears to flash quickly, and then
      repaint.
- -black
- Use a black background. This can be somewhat disorienting as everything
      goes black for a moment.
- -solid color
- Use a solid background of the specified color. Try green.
- -root
- Use the root window background.
- -none
- This is the default. All of the windows simply repaint.
- -geometry WxH+X+Y
- Specifies the portion of the screen to be repainted; see X(7).
- -display display
- This argument allows you to specify the server and screen to refresh; see
      X(7).
- -version
- This argument prints the program version and exits.
The xrefresh program uses the routine XGetDefault(3) to read
  defaults, so its resource names are all capitalized.
  - Black, White, Solid, None,
     Root
- Determines what sort of window background to use.
- Geometry
- Determines the area to refresh. Not very useful.
  - DISPLAY - To get default host and display number.
It should have just one default type for the background.
Jim Gettys, Digital Equipment Corp., MIT Project Athena