Changing Your Shell
Running chsh will place you into the editor that is in your EDITOR environment variable; if it is not set, you will be placed in vi

You can also give chsh the -s option; this will set your shell for you, without requiring you to enter an editor. For example, if you wanted to change your shell to bash, the following should do the trick:

chsh -s /usr/local/bin/bash

Note:
The shell that you wish to use must be present in the /etc/shells file. If you have installed a shell from the ports collection, then this should have been done for you already. If you installed the shell by hand, you must do this.

For example, if you installed bash by hand and placed it into /usr/local/bin, you would want to:

echo "/usr/local/bin/bash" >> /etc/shells