Files for configuring your shell

/etc/profile     
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.

/etc/bashrc   
 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.

~/.bash_profile 
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

~/.bashrc         
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.
 
~/.bash_logout   
Executes when you log out of your bash shell.
 By default just simply clears the screen.(this is also for a particular user)