$ whoami
   $ whoami
      $ whoami
         $ whoami: not who you think
$ . readme.md
sourcing: ./readme.md
> sourcing: ./readme.md
> > sourcing: ./readme.md
> > > [SIGLOOP]
$ ps
  PID  TTY  STAT  CMD
    1    ?    R   /sbin/self
    1    1    R   /sbin/self
    1    1    R   /sbin/self
$ history 3
  998  cat README.md
  999  cat README.md
 1000  cat README.md
$ exit
exit: there is no exit
$ exit
exit: you are still here
$_

the file you are reading is reading you.