less.1 -iFRX -x4
opposite of more
-i or --ignore-case
       Causes searches to ignore case; that is, uppercase and lowercase are considered  identical.   This
       option  is  ignored  if  any  uppercase letters appear in the search pattern; in other words, if a
       pattern contains uppercase letters, then that search does not ignore case.
-F or --quit-if-one-screen
       Causes less to automatically exit if the entire file can be displayed on the first screen.
-R or --RAW-CONTROL-CHARS
       Like -r, but only ANSI "color" escape sequences are output in "raw" form.  Unlike -r,  the  screen
       appearance  is maintained correctly in most cases.  ANSI "color" escape sequences are sequences of
       the form:

            ESC [ ... m

       where the "..." is zero or more color specification characters For the purpose of keeping track of
       screen  appearance,  ANSI color escape sequences are assumed to not move the cursor.  You can make
       less think that characters other than "m" can end ANSI  color  escape  sequences  by  setting  the
       environment  variable  LESSANSIENDCHARS  to  the  list  of characters which can end a color escape
       sequence.  And you can make less think that characters other than the  standard  ones  may  appear
       between  the  ESC  and  the  m by setting the environment variable LESSANSIMIDCHARS to the list of
       characters which can appear.
-X or --no-init
       Disables sending the termcap initialization and deinitialization strings to the terminal.  This is
       sometimes desirable if the deinitialization string does something unnecessary, like  clearing  the
       screen.
-xn,... or --tabs=n,...
       Sets tab stops.  If only one n is specified, tab stops are set at multiples  of  n.   If  multiple
       values  separated by commas are specified, tab stops are set at those positions, and then continue
       with the same spacing as the last two.  For example, -x9,17 will set tabs at positions 9, 17,  25,
       33, etc.  The default for n is 8.
source manpages: less