What are the color names in TERM=xterm256 for colors > 16?

Question

I'm trying to set my xterm background color to "color 234" in xterm256 color mode, but I don't know what to pass to the "-bg" option. I've tried "color234", "Color234", but those are not defined.

Answer 1

The bg option sets the X window background and has nothing to do with the emulation or the 256-color escape codes interpreted by the terminal.

You can find more about the escape codes that the terminal interprets at http://rtfm.etla.org/xterm/ctlseq.html .

According to the documentation, the escape sequence is:

• ESC [ 38;5;xxxm (To set the background)
• ESC [ 48;5;xxxm (To set the foreground)

Where xxx is the color value as follows:

• 0-15 are the standard ANSI colors
• 16-231 are a 6x6x6 RGB color cube given by ((36 * r) + (6 * g) + b + 16) with r,g,b in [0..5]
• 232-255 are a greyscale ramp without black and white.

The other commenter was correct about setting the background color of the window to 0x1C1C1C with xterm -bg rgb:1c/1c/1c, as Color #234 in the 256-color Xterm emulation is a dark grey of 0x1C1C1C as computed by http://www.vim.org/scripts/script.php?script_id=1349:

Answer 2

xterm -bg rgb:1c/1c/1c is how you'd set the color using RGB values.

Answer 3

Here is a chart of X11 color names.

You may have /etc/X11/rgb.txt on your system.