What is the purpose of PHP having a symbol (the dollar sign) in front of each variable? [duplicate]

Answer 1

Having a symbol to denote variables makes string interpolation simple and clear. Shell, Perl and PHP grew out of the need for quick and easy string manipulation, including interpolation, so I imagine using a variable prefix seemed like a good idea.

I.e. in PHP:

$var = 'val';
$strVar = "The var is $var";

Compare to typical string formatting:

var = 'val'
strVal = 'The var is %s' %(var)

Answer 2

I think it's just from it's origins.
unix shell and Perl were examples.
if you watch PHP closer you will see very much in common with shell.
Thus, you'd better address your question there :)

Answer 3

In php you don't have to set the variables prior to using it, in other languages you have to declare variables before using it like var MyVar = 'my value' or defining what kind of content is going to hold.

I'm not sure but I think the purpose of adding a symbol was to not have to declare variables and let apache know that this is a variable.