The emulated terminals, GNOME terminal or LXTerminal, are non-login shells. The start-up script is ~/.bashrc, not ~/.bash_profile. If we want to modify the PATH variable for the emulated GNOME terminal, for example, it should be modified in ~/.bashrc.
On the other hand, ~/.bash_profile is read by login shells. To go to a login shell, type Ctrl+Alt+F1 to swich to tty1, for example. The desktop usually runs at tty3, we can switch back by Ctrl+Alt+F3.
There is also ~/.profile, which is for the generic shell sh (bash is a specific implementation of sh). Its documentation says “~/.profile: executed by the command interpreter for login shells. This file is not read by bash(1), if ~/.bash_profile or ~/.bash_login exists.”
To get a consistent environment across the login shells and the non-login shells, source ~/.bashrc in ~/.bash_profile. Also include ~/.profile in ~/.bash_profile. Here is what ~/.bash_profile looks like:
if [ -r "${HOME}/.profile" ]; then
. "${HOME}/.profile"
fi
if [ -r "${HOME}/.bashrc" ]; then
. "${HOME}/.bashrc"
fi
The terminal of Mac OS is an emulated non-login shell. That said, ~/.bashrc, not ~/.bash_profile, should be edited for the shell environment. Later versions of Mac OS terminal runs Z shell. To find out the name the current shell, ps -p $$. For zsh, edit ~/.zshrc.