When Bash is invoked as an interactive login shell it first reads and
executes commands from the file /etc/profile, if that file
exists. After reading that file, it looks for
/.bash_profile, /.bash_login, and
/.profile, in that order, and reads and executes commands
from the first one that exists and is readable. When a login shell
exits Bash reads and executes commands from the file
/.bash_logout, if it exists.