Profiles

cd /etc

cat profile
cat bash.bashrc

cd $home
cat .bashrc
cat .bash_profile

When you login (type username and password) via console, either sitting at the machine, or remotely via ssh: .bash_profile is executed to configure your shell before the initial command prompt.

But, if you've already logged into your machine and open a new terminal window (xterm) inside Gnome or KDE, then .bashrc is executed before the window command prompt. .bashrc is also run when you start a new bash instance by typing /bin/bash in a terminal.
—http://www.joshstaiger.org/archives/2005/07/bash_profile_vs.html

And a good tip...

Most of the time you don't want to maintain two separate config files for login and non-login shells - when you set a PATH, you want it to apply to both. You can fix this by sourcing .bashrc from your .bash_profile file, then putting PATH and common settings in .bashrc.

To do this, add the following lines to .bash_profile:

if [ -f ~/.bashrc ]; then
	 source ~/.bashrc
fi