By default, Ubuntu configures the root and the first user created to the bash shell. This is the traditional shell. Any users created from this shell will also be given the same bash shell. We will discuss the configuration files and commands related to the bash shell. The system-wide settings files can be located in the folder /etc. Some of the most important ones are bash.bashrc, bash_completion, profile, and scripts stored in the /etc/bash_completion.d folder:

The same files are supplemented and you can override them as hidden files in each users' home directory. The files are .bashrc, .bash_history, .bash_logout, and .profile, as shown in the following screenshot: