cat myfilecat can be used to combine (concatenate) files and hence the rather odd name. For example:-
cat f1 f2 f3concatenates files f1 and f2 into the file f3. The command more types out a file one screenful at a time e.g.:-
more myfile
The command less is very similar.
The commands head and tail can be used to type the first or last few lines of a file, for example:-
tail -3 myfiletypes out the last three lines of myfile.