I have some no graphics card (“headless”) server that I have to operate via the serial port as the console to install Linux, VMware, and other OSes. For a terminal server I use a Linux box with a USB serial device.

So from my Mac in a terminal window I SSH into the Linux box, and from there run the screen utility to emulate a terminal to the USB port. The problem will also show up if I use Putty from a Windows system.

When color VGA character styled menus come up—BIOS setup or installs scripts usually—some of the critical characters are invisible (Like “Press F9 to Continue”). The reason is that they are programmed for light gray over cyan—or something like that—and the foreground and background of the charcters end up being the same color.

A sometimes-workaround is to click and drag the mouse over the affected area, and the inverse of the colors renders enough contrast to make the characters visible.

Can someone advise me how to alter the color palette of the terminal emulation so this doesn’t happen?

I think this might be affected by the TERM environment variable but I am not sure if it is the one on the Mac, the Linux box or both.


The description sounds like anaconda/whiptail dialogs, but a screenshot would help clarify this.

However, for general advice: changing the color palette based on the setting for TERM has limited effectiveness, because

  • some applications hard-code "ANSI color escapes"
  • while some can use the xterm control sequences for setting color palettes, that can be complicated

Another problem is that Terminal.app and PuTTY use different palettes for the basic colors (whether you count them as 8 ANSI, or 16 or whatever).

Both programs allow you to customize these colors however. I do this with PuTTY to work around its exceptionally dark blue which is almost invisible against a black background.

Here are a few links which discuss changing color palettes on these terminals:

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