By default, SWI-Prolog will use colored output on the commandline based on library(ansi_term) if current_output is connected to a terminal. This is detected by the tty property of streams (see stream_property/2). Coloring can be controlled in two ways

• It can be disabled using this in your personal initialization file (see below).

  :- set_prolog_flag(color_term, false).

• Colors can be changed by message type (see print_message/2) using the hook message_property/2.

See also

- PlInitialisation.txt for editing your personal init file.