How $ variable works?

Question

how $ variable works in php

$a="name";
$a="age";
echo $name;

//output : age

Answer 1

$name = $(name)=$($a) = $a = age

Answer 2

variables with $ change their name according to the string the one with only $ contains.
so in your example $a becomes $name, because $a contains the string "name".

I'm still searching for a practical use for this. never needed it before. can be really confusing.