Is it possible to remove the $ from an environment variable? I'm on Mac and have just created an environment variable inside the .bash_profile directory, it works fine when I run: 

$variable_name


I just want the know why the dollar sign is there and if it is possible to remove it. Any help would be appreciated :)
The $ (dollar sign) is there to reference variables in bash.  You cannot remove it.  Technically, it's called variable/parameter expansion.  Basically the value of the variable is "expanded out". 

Using variables in bash is pretty straight forward:


Don't use a "$" when setting a variable
Use the "$" when referencing/calling a variable


Example:

#!/bin/bash
var1=Hello
read var2
echo $var1 $var2
exit


In the above script, we set var1 to "Hello" and var2 to user input (assume "World").  The next command prints out the contents of both variables on a single line:

Hello World


For more details, it's best to start with a good tutorial:  BASH Programming - Introduction HOW-TO.  Also have a look at the Bash Reference Manual

Tip:

You can enclose the variable in braces - ${variable}.  This serves to "protect" the variable from characters immediately following the variable name which would (incorrectly) become part of the variable

Example:

var1=foo
echo $var1bar
echo ${var1}bar


The first echo would produce nothing since the variable var1bar doesn't exist where as the second echo would produce the word foobar as expected.  Personally, I use braces for all my variables as a matter of style.