There are several files which are automatically read when you start a shell.
From the bash manual page (FILES section):
Code:
/etc/profile
The systemwide initialization file, executed for login shells
~/.bash_profile
The personal initialization file, executed for login shells
~/.bashrc
The individual per-interactive-shell startup file
~/.bash_logout
The individual login shell cleanup file, executed when a login shell exits
Note that you will have to re-start you X session for environment variables set in these files to be available to programs you start from whatever X launcher you use (e.g. the K menu or the gnome panel). For programs started from a shell, you only need to start a new shell.