Sort of, depending on what you're thinking. I believe it can only be used in these ways as a command shell to Unix:
Using relevant Java class methods (or Beanshell equivalents) to do things you normally do in command shell (e.g. file I/O, execute applications, move/rename/delete/create files/directories, etc.). So you'll be using Java code to do it rather than shell commands/scripts, and this Java code will execute via Beanshell like interactive script rather than compile then execute with normal Java. This approach is same as using Python, Ruby, or Perl as a replacement for Unix shell, via their interfaces for interactive console/shell vs option to execute a written script file.
Using Beanshell Java code to make shell calls to call the actual Unix shell commands you want to run. Frankly, there's not much point to doing it this way. More work just to do same thing as using normal Unix shell.