less command and syntax highlighting

less doesn't support syntax highlighting.

vim, like all vi clones has a read-only mode called view which you can use to just view files. it supports all features of vim including syntax highlighting.

e.g.

view filename.py

the main difference between view and vi is that view doesn't "lock" the file you're viewing by creating a .swp file.

Syntax highlighting of less, works just fine on most *nix systems.

apt install source-highlight
export LESSOPEN="| /usr/share/source-highlight/src-hilite-lesspipe.sh %s"
export LESS=' -R '

On Fedora/RedHat based distros use /usr/bin/src-hilite-lesspipe.sh instead.

Even on Cygwin you can do it with the minor adjustment of the shell script path and installing with apt-cyg instead of apt.

However, using this drastically slows down browsing of large files. I suggest to use alias in such a way to only implement the LESSOPEN export above when needed, like this:

alias lessh='LESSOPEN="| /usr/bin/src-hilite-lesspipe.sh %s" less -M '

where the -M flag is convenient to also show filename and line number.

Also remember to copy the script into your bin path:

cp /usr/share/source-highlight/src-hilite-lesspipe.sh /usr/bin/src-hilite-lesspipe.sh

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UPDATE: 2019-07-24

Apparently, on more recent Cygwin installs, you have the following files in your path:

source-highlight.exe
source-highlight-esc.sh
source-highlight-settings.exe

So now you also need to execute the source-highlight-settings.exe that will add the configuration file:
$HOME/.source-highlight/source-highlight.conf.

I tend to disagree with Ingo, less can be taught to highlight syntax. Check out this answer on SuperUser. Basically, you have to install GNU's source-highlight (available in all major distro package repos), and then add the following to your .bashrc (or .bash_profile or what have you):

export LESSOPEN="| /path/to/src-hilite-lesspipe.sh %s"
export LESS=" -R "

However, note that source-highlight is not as powerful as vim's highlighter. Use whatever suits you best.