Welcome to the CHICKEN Scheme pasting service

0 andyjpb@robusta ~
$ echo $LESS
$LESS       $LESSCLOSE  $LESSOPEN   

0 andyjpb@robusta ~
$ echo $LESS
-X -F

0 andyjpb@robusta ~
$ echo $LESSCLOSE 
/usr/bin/lesspipe %s %s

0 andyjpb@robusta ~
$ echo $LESSOPEN 
| /usr/bin/lesspipe %s

LESSOPEN(1)                 General Commands Manual                LESSOPEN(1)

NAME
       lessfile, lesspipe - "input preprocessor" for  less.

SYNOPSIS
       lessfile, lesspipe

DESCRIPTION
       This manual page documents briefly the lessfile, and lesspipe commands.
       This manual page was written  for  the  Debian  GNU/Linux  distribution
       because the input preprocessor scripts are provided by Debian GNU/Linux
       and are not part of the original program.

       lessfile and lesspipe are programs that can be used to modify  the  way
       the  contents of a file are displayed in less.  What this means is that
       less can automatically open up tar files, uncompress gzipped files, and
       even display something reasonable for graphics files.

       lesspipe  will toss the contents/info on STDOUT and less will read them
       as they come across.  This means that you do not have to wait  for  the
       decoding  to  finish  before  less shows you the file.  This also means
       that you will get a 'byte N' instead of an N% as  your  file  position.
       You  can seek to the end and back to get the N% but that means you have
       to wait for the pipe to finish.

       lessfile will toss the contents/info on a file  which  less  will  then
       read.   After  you  are done, lessfile will then delete the file.  This
       means that the process has to finish before you see  it,  but  you  get
       nice percentages (N%) up front.

-----
if [ -x /usr/share/source-highlight/src-hilite-lesspipe.sh ]; then
        export LESSOPEN="| /usr/share/source-highlight/src-hilite-lesspipe.sh %s"
        export LESS=' -R '
fi
-----

https://www.gnu.org/software/src-highlite/

https://packages.debian.org/jessie/source-highlight

http://packages.ubuntu.com/search?keywords=source-highlight