grabc is s simple but very useful program to determine the color string in hex (or in RGB components) by clicking on a pixel on the screen. While web browsing, lots of time you find a nice color and wonder what color is that. Well just use grabc!
When this program is run, the mouse pointer is grabbed and changed to a cross hair and when the mouse is clicked, the color of the clicked pixel is written to stdout in hex prefixed with #. It will the R, G, B component also in the stderr.