I used xsetroot -solid "#xxxxxx" to set a background color. I like this color, but did not record the command and it's long gone from the bash shell history. How can I find out what the color was?
I would just use the Color Picker tool from Gimp, which will let you click anywhere on the screen and will give you the RGB value for the color at that point.
Assuming it still is the color of the root window: run
xcolorsel (part of the contributed X utility set; some distributions pack it separately), click the “Grab color” button, and click somewhere on your root window. The numbers you want are the ones below the color list box. Change the display format to “8 bit scalred rgb” to have something familiar.
Use well known color names compilation https://en.wikipedia.org/wiki/X11_color_names:
$ apt-file search rgb.txt ... x11-common: /etc/X11/rgb.txt ... $ less /etc/X11/rgb.txt