How to find a file in the ubuntu

In my experience ,I was intent to find my "tes.php" file in the ubuntu  where is usually locate in the folder /var/www/. But in the case we don't know where is the file locate, we can find a file in command terminal with the command below :

find / -iname 'tes.php' , if we already on the root previledge , but if not you should write with :
sudo find / -iname 'tes.php'


or we want to find file with particular extention, for example php. we can use :


find / -iname '*.php' or

sudo find / -iname '*.php'

and the files with extention .php will appear like the figure below.