Login bash reads ~/.bash_profile
, interactive bash - ~/.bashrc
. See Bash Startup Files for more details.
When you open a terminal window it starts bash in the interactive mode which makes bash read ~/.bashrc
. Settings from ~/.bash_profile
are normally read when you log into the desktop, so that when ~/.bash_profile
is changed you need to re-login for the changes to apply.
People often make ~/.bash_profile
invoke ~/.bashrc
as well, so that you get the same environment in both modes.