/bin/bash is the shell for BASH
In the /etc directory, the "profile" file (controlled by root) contains the default environment for every user.
Each user may optionally have a .bashrc file which gives them unique environment attributes.
To see your environment, when logged in, type "env"
To determine the shell you are using, type "env | grep SHELL" and you'll see the environment variable that defines the shell you are using.