When bash is invoked as an interactive non-login shell, it reads .bashrc but not .bash_profile. When bash is it is invoked as an interactive login shell, it reads .bash_profile but not .bashrc.
Terminal and iTerm open new shells as login shells by default, so many OS X users just use .bash_profile as their personal configuration file. For example tmux and the shell mode in Emacs open new shells as non-login shells though.
출처: https://apple.stackexchange.com/questions/99688/how-to-persistently-define-aliases-in-terminal