gistfile1.txt

When  bash is invoked as an interactive login shell, or as a non-inter-
       active shell with the --login option, it first reads and executes  com-
       mands  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.  The --noprofile option may be  used  when  the
       shell is started to inhibit this behavior.