Add `--color=auto/always/never`

[cblp]

As in git

Also, check terminal detection under docker.

always — colorize the output unconditionally never — do not colorize the output auto [default] — detect if we are running in a terminal (isatty?) and colorize only if in terminal

[willbasky]

What auto acts?

[cblp]

added to the description

[willbasky]

auto [default] — detect if we are running in a terminal (isatty?) and colorize only if in terminal

Can ff be launched not in terminal?

[cblp]

Yes, when launched from a script or a command, like ff | less, stdout is a pipe, not a terminal (teletype, tty).