To install lighttpd with PHP:
sudo aptitude install lighttpd php5-cgi,sudo lighty-enable-mod fastcgisudo lighty-enable-mod fastcgi-phpsudo service lighttpd force-reloadTo sum up:
sudo aptitude install lighttpd php5-cgi sudo lighty-enable-mod fastcgi sudo lighty-enable-mod fastcgi-php sudo service lighttpd force-reload
On some documentation, even in the default index page displayed by lighttpd, the server document root is not /var/www/ but /var/www/html/.
When you close the last WSL console, lighttpd will also be closed. To relaunch, type sudo service lighttpd start.