Shell From Hackepedia
A shell is both a command language and a programming language (interpreted) that provides an interface to any UNIX based operating system UBO. The most popular shell by far is bash which is provided by the GNU team. There are several other popular shells, depending on your requirements and skillset:
$ echo $SHELLwhich is one of the variables that can be found in your environment. You can get a list of all of your environment variables:
$ envas you can see, there is where you will change items such as your PATH