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.
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[48;5;***xxx***m (To set the background)
- ESC[38;5;***xxx***m (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: alt text http://www.frexx.de/xterm-256-notes/img/256colors2.png
You may have
/etc/X11/rgb.txt on your system.