Simple test: Log in on the console in text mode. Say "echo ESC [ 31 m Hallo ESC [ 32 m world ESC [ 0 m" in your favorite shell. In that string, typing the escape character requires some quote character (in my shell it's control-V, and escape is typed as control-[, opening square bracket), and there are no spaces between Escape, [ 31 and m. If you do this, you should see Hallo in green and world in red, or the other way round (I can never remember the ANSI codes).
If this works: Then the terminal driver itself is OK, and your other changes don't. If this doesn't even work, then I think you need to go down to the hardware level (screen interface like VGA or HDMI, GPU driver).
Nice trick --
echo needs the -e option to display plain text escape sequences now-- I'm not sure why, especially since the -e option isn't documented in
echo(1).
Furthermore, this command:
echo -e '\033[31mHello \033[32mWorld!\033[0m' works if
/bin/sh is my shell, but not if
/bin/csh is my shell. This is because sh implements echo with the external command
/bin/echo, but csh implements echo as a builtin command.
builtin(1)
To output in color as root, I can still use:
/bin/sh -c "echo -e '\033[31mHello \033[32mWorld!\033[0m'"
Edited to add:
Rather than using hard-coded escape sequences, the preferred method nowadays is to use
tput terminal control sequences. In FreeBSD,
tput AF [0-255] changes the foreground color, and
tput AB [0-255] changes the background color. In Linux, substitute "setaf" for "AF" and "setab" for "AB" -- this is because, by default, FreeBSD uses
termcap terminal capability codes, whereas Linux uses
terminfo capcodes. Furthermore, note that installing ncurses or other programs may change the terminal capability database used by the
tput command. On the more positive side however, the tput method should work regardless of shell or echo program versions.
TERM must be set to "xterm-256color" to use a fuller range of 256 ANSI colors. "xterm" (and most other terminal types) will only use the first 8-16 colors. For non-ANSI terminals which only support 8-16 colors, it might be necessary to use the alternate capcodes Sf and Sb to set foreground and background colors (or, for terminfo, setf and setb).
Edited again to add: Instead of
echo -e '\033[31mHello \033[32mWorld!\033[0m' you can also use this newer syntax, with a $ prefix before the single quote:
echo '$\033[31mHello \033[32mWorld!\033[0m' -- I believe this should work in more recent versions of FreeBSD regardless of shell or echo implementations.
