I have been using the Emacs "shell" command for many years. It starts a shell in the current buffer. This seems to be the case up through Emacs 24.
I am now running Emacs 25 (on Linux) and I'm finding that the shell command works differently. It starts (or goes to) the shell in a different buffer, splitting the current window if necessary. Sometimes the shell goes to the current buffer, sometimes to the other buffer (if I'm displaying two buffers).
What gives? How can I have the shell command work the way it used to?