If you want to redirect your main domain to a sub directory, then you are on a right page.

Just put below lines of code in the .htaccess file –

RewriteCond %{HTTP_HOST} ^(www.)?lokesh-gupta.com$ [NC]
RewriteRule !^holi/ /subdirectory%{REQUEST_URI} [L,NC]

You need to put above .htaccess in the root directory of the domain which you want to redirect.