Sets up user information for every user.
It is executed when you first log in.
It sets up the path as well as the environmental variables,the location of your mailbox and size of your history files.
Finally,files under the /etc/profile.d are executed.
Runs for every user who runs the bash shell.
It sets a default prompt and may add one or more aliases.
But this file can be overridden by information in ~/.bashrc file.
It is run when the particular user logs in.
Used by the user to enter information that is specific to his or her own use of the shell.
This file inturn calls the user's .bashrc file
Contains the information specific to the particular user.
This is the best location to add environmenta variables and your aliases so that shell
will pick up when you log in.
Executes when you log out of your bash shell.
By default just simply clears the screen.(this is also for a particular user)