When bash is invoked as an interactive login shell, or as a non-interactive shell with the --login option, 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.  The --noprofile option  may
       be used when the shell is started to inhibit this behavior.

       When  a  login  shell  exits,  bash  reads  and executes commands from the files ~/.bash_logout and /etc/bash.bash_logout, if the files
       exists.

       When an interactive shell that is not a login shell is started, bash reads and executes commands from ~/.bashrc, if that  file  exists.
       This  may  be  inhibited  by  using the --norc option.  The --rcfile file option will force bash to read and execute commands from file
       instead of ~/.bashrc.

       When bash is started non-interactively, to run a shell script, for example, it looks for the  variable  BASH_ENV  in  the  environment,
       expands  its  value if it appears there, and uses the expanded value as the name of a file to read and execute.  Bash behaves as if the
       following command were executed:
              if [ -n "$BASH_ENV" ]; then . "$BASH_ENV"; fi
       but the value of the PATH variable is not used to search for the file name.