The linux console is tighed to 16 colors (or 8 depending on the setup), but something I didn’t know, is that you can choose them through the whole bunch of 256 colors. Linux has escape sequences to change those if it has been enabled in the kernel.

The escape sequences

The format is simple once you know it, and you can find them all in the console codes manual page: (in ESC- but not CSI-sequences section)

<ESC>]P{index}{hex red}{hex green}{hex blue}

Where index is the set of ANSI colors:

• 0 black and foreground
• 1 dark red
• 2 dark green
• 3 brown
• 4 dark blue
• 5 purple
• 6 dark cyan
• 7 light gray
• 8 dark gray
• 9 red
• A (10) green
• B (11) yellow
• C (12) blue
• D (13) magenta
• E (14) cyan
• F (15) white and foreground

Then RGB components are specified in hexadecimal values. So changing the background color (0) to #222222 is as simple as echo’ing:

$ echo -en '\e]P0222222`

A clear is necessary after setting colors because existing characters are not modified. That’s what I have put in my login startup script:

if [ "$TERM" = 'linux' ]; then
  # set custom colors on ttys
  concol() { echo -en "\e]P$1$2$3$4"; }
  concol 0 2f 34 3f # black/background
  concol 1 a9 63 5d # dark red
  concol 2 46 84 59 # dark green
  concol 3 84 76 3d # brown
  concol 4 58 79 af # dark blue
  concol 5 9c 65 94 # purple
  concol 6 00 85 92 # dark cyan
  concol 7 d8 d8 d8 # light gray
  concol 8 77 77 77 # dark gray
  concol 9 ff bb b2 # red
  concol A 9d de af # green
  concol B e0 ce 91 # yellow
  concol C b3 d1 ff # blue
  concol D fa bd f0 # magenta
  concol E 79 e0 ed # cyan
  concol F ff ff ff # white/foreground
  clear
fi

Here is the result of dircolors --print-ls-colors (yes, the background is the same colors than my blog pages background ^^):

And before login?

That works once you logged in, but until there you’re stuck with default ones. The solution is to use the issue display from agetty which shows text before the login prompt. I am more used to have a clean and empty screen for login, so my agetty run command usually has the --noissue argument, but putting only an escape sequence gives the same effect:

# from your services manager (mine is dinit)
$ agetty --nonewline --nohints --nohostname linux

With the following /etc/issue:

\e]P02f343f\e[H\e[J

Where \e[H moves cursor to the origin of the screen and \e[J erases all from the cursor.

I also keep the login program ending in timeout and relaunching when needed on other ttys:

# from your services manager
$ agetty --nonewline --login-pause --timeout 10 --nohints --nohostname linux

And from boot?

There is a way to enable this as soon as the ramdisk is loaded, by echo’ing the right sequence in a script included in the initrd, but as my startup is really fast (1 second or 2) I thought it was not worth trying it.