[yonatan]

       By  default,  color is not used to distinguish types of files.  That is
       equivalent to using --color=none.  Using the --color option without the
       optional  WHEN  argument  is  equivalent to using --color=always.  With
       --color=auto, color codes are output only if standard  output  is  con-
       nected  to  a  terminal  (tty).  The environment variable LS_COLORS can
       influence the colors, and can be set easily by the dircolors command.

מתוך man ls

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