refresh all or part of an X screen
xrefresh [-option ...]
-white Use a white background. The screen just appears to flash quickly, and then repaint. -black Use a black background (in effect, turning off all of the electron guns to the tube). This can be somewhat disorient‐ ing 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
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.