Both emacs and tcsh use tab filename completion. Here is how this works: Start typing the name of the file and then hit Tab to ask for the rest of the name. You get all of it if the first letters you have typed are enough to identify the file uniquely. If not, you get more characters up to the point where more information is needed.
For example, suppose you have only the following files in a directory:
lab01 lab05 lab13If you type l followed by the Tab key you will see lab. At this point the next character could be a 0 or 1. Suppose you wanted lab13. Then hitting 1 and Tab would give you the result. This feature is especially useful for much longer names and saves quite a bit of typing.
The same method works with commands in tcsh and bash. Start typing em followed by Tab and you get emacs.