Please don't mark it as duplicated. I've tried a lot but can't make it working.

I've installed LAMP using tasksel.
Everything is fine but having file permission error (While installing WordPress I get this error "Sorry, but I can’t write the wp-config.php file." )

I can create the file manually but I don't want to do this. I wasn't to make it working correctly.

What I did to set up permission after installing lamp

cd /var/wwww/
sudo chown -R username:www-data /var/www/html/
sudo chmod 775 /var/www/html/
sudo chmod g+s /var/www/html/

Later I tried some solutions like sudo chown -R [USER NAME]:[USER NAME] /var/www which I found on askubuntu.

I don't know much about permission issue trying solution blindly.

Can you please help me on this to make it working? :)

Output of ls -l /var/www

Output of total 4
drwxrwsr-x 3 h3mdsa h3mdsa 4096 Jun 12 16:40 html

(Thanks @Jos for comment)

Thanks in advanced,

Md Al Amin