bash and tcsh are different in many ways, and are good for different things. First a bit of history.

In the beginning was only ‘sh’, the “Bourne Shell”. It was written to do scripting reasonably well, but for interacting with users it left a lot to be desired.

Then somebody came up with ‘csh’, the C-shell, which had better job control and several differences in syntax which generally made it better for interactive use. Some people did scripting in ‘csh’ but most realized it’s terrible for that, so they used ‘csh’ for interactive shells and ‘sh’ for scripts. This was a bit of a pain because you had to remember two different syntaxes, but that’s how it was.

Then came ‘ksh’ which was ‘sh’ but slightly better for scripting and much better for interactive use, possibly as good as ‘csh’.

Then came ‘tcsh’ with made a big leap in capabilities for interactive use. This continued the split. ‘sh’ or ‘ksh’ for scripts, ‘tcsh’ for interactive.

Then came ‘bash’. This picked up almost every feature that’s good for interacting with a user, and retained all the features that are good for programming.

Today ‘bash’ is widely-accepted, and probably the most-used shell ever, and ‘tcsh’ is only used by a few people, mostly people that love the C-shell syntax with all of ‘tcsh’s added features. It’s still a good shell (I used it as my default shell for over 10 years), but ‘bash’ is just as good for interactive use, and much better for programming, so most people just use it for both, and not have to remember both styes of syntax.

As to what’s really DIFFERENT in each, you’d have to use each for a while to see everything. They use different syntax for for / foreach loops. You set the prompt in different ways. Aliases are handled differently. They read different files when they start up.