Xwin Colors 

cmd:rgb 

The Xwin comes with a predefined set of colors, liseted in the file rgb.txt

rgb uses the default color name database of usr/openwin/lib/X11/rgb.txt to builds a color name database in dbm format.

rgb file under X11R6 

! $XConsortium: rgb.txt,v 10.41 94/02/20 18:39:36 rws Exp $
255 250 250             snow
248 248 255             ghost white
248 248 255             GhostWhite
245 245 245             white smoke
245 245 245             WhiteSmoke
220 220 220             gainsboro
255 250 240             floral white
255 250 240             FloralWhite
253 245 230             old lace
123456789-123456789-123456789-123456789-123456789-123456789-123456789-123456789
         1         2         3         4         5         6         7

— same version as that of openwin

color listing 

$ head /usr/openwin/lib/X11/rgb.txt
! $XConsortium: rgb.txt,v 10.41 94/02/20 18:39:36 rws Exp $
255 250 250             snow
248 248 255             ghost white
...

List all colors 

ls /usr/X11R6/lib/X11/rgb.txt
head !$ | cut -f 3 | tail +2
[Tip]

!!

Found that each multi-word color have a corresponding one-word color version

$ grep '[[:alnum:]] [[:alnum:]]' -A 1 /usr/X11R6/lib/X11/rgb.txt | less
248 248 255             ghost white
248 248 255             GhostWhite
245 245 245             white smoke
245 245 245             WhiteSmoke
220 220 220             gainsboro
255 250 240             floral white
255 250 240             FloralWhite
253 245 230             old lace
253 245 230             OldLace
250 240 230             linen
250 235 215             antique white
250 235 215             AntiqueWhite
255 239 213             papaya whip
255 239 213             PapayaWhip
255 235 205             blanched almond
255 235 205             BlanchedAlmond
255 228 196             bisque
255 218 185             peach puff
255 218 185             PeachPuff
255 222 173             navajo white
255 222 173             NavajoWhite

one-word-version 

awk 'NF==4 {print }' < /usr/openwin/lib/X11/rgb.txt

— print all one-word-version-of colors

awk 'NF==4 {print $4}' < /usr/openwin/lib/X11/rgb.txt
awk 'NF==4 {printf $4 " "}' < /usr/openwin/lib/X11/rgb.txt

— print all one-word-version-of color names only

ls /usr/X11R6/lib/X11/rgb.txt
head !$ | grep -iv grey | awk 'NF==4 {printf $4 " "}' | fold -s -w 72 | ssur '\\' | sed 's/"\\/" \\/g'
^head^cat^ | xsel -c

— grey is just synonym of gray

awk 'NF==4 {printf "'\''#%02x%02x%02x'\'' %s\n", $1, $2, $3, $4 }' < /usr/openwin/lib/X11/rgb.txt

— print all one-word-version-of color and its correspondent hex value