How to get 256 colors in a standard Linux terminal + screen (without X windows).

.bash_profile

# ...

# This is for what I would consider a standard setup, where TTY's 1 -- 6 are
# "linux" terminals and TTY's 7+ are reserved for X windows.  You should adjust
# it to your setup, accordingly.
#
# ::: Important ::: You must have both fbterm and screen installed and on your
# path for this to work.

virtual_terminal="$( tty | grep -oE ....$ )"
case "$virtual_terminal" in
  tty1|tty2|tty3|tty4|tty5|tty6)
    exec fbterm -- bash -c 'TERM=fbterm screen'
  ;;
esac

# I had an issue invoking `TERM=fbterm screen` with `fbterm` directly -- it
# seems to want the actual command to invoke as the first parameter (rather than
# an environment variable).  I worked around it by using `bash -c`; you may use
# whatever shell you want, or may even be able to figure out how to invoke
# `TERM=fbterm screen` directly.
#
# To get the 256 color mode to work correctly, invoking `screen` with
# `TERM=fbterm` is necessary.  It wouldn't work correctly simply exporting the
# variable before or after invoking `screen`.
#
# This is what the official fbterm documentation says about 256 color mode:
#
# xterm has a 256 color mode extension, FbTerm also add it in this version. But
# xterm's 256 color escape sequences conflict with the linux sequences
# implemented by FbTerm, so private escape sequences were introduced to support
# this feature:
#
# ESC [ 1 ; n }                   set foreground color to n (0 - 255)
# ESC [ 2 ; n }                   set background color to n (0 - 255)
# ESC [ 3 ; n ; r ; g ; b }       set color n to (r, g, b) ,  n, r, g, b all in (0 - 255)
#
# and a new terminfo database entry named "fbterm" was added to use these
# private sequences, all program based on terminfo should work with it. By
# default, FbTerm sets environment variable "TERM" to value "linux", you need
# run "TERM=fbterm /path/to/program" to enable 256 color mode.

# ...