Solution Provided for Exercise requires unfamiliar command variant-shell change

[juliebates]

2 things:

1. tcsh hasn't been functionally introduced yet, even though it is listed as one of the commonly used neuroimaging projects shells. Novice user will be distracted by 'how do I give the command' or 'is there a general command' rather than identifying which shell to list, and may not ever reference the list.
2. a novice may read the solution and conclude that tcsh is a general command to change shells in a current session, not having seen that command before (I did not see it anywhere in tutorial). but IF I understand the question, there are numerous correct answers (e.g any of the shells listed for example).
   One way to clarify might be to just edit the solution, with provision of two different examples of shell change commands, e.g.

e.g Change shell TO KornSHell
% ksh or $ ksh (same command, different prompt)
OR
e.g. Change shell TO a C-programming language type shell
% csh (or tcsh)

Plus a comment: Successful shell change will be indicated with ~>