Both cat and myfile are files. In this above command cat will be executed and run as processes. myfile will not be executed. Instead, myfile will be passed as argument to the program called cat.

Both cat and myfile are files. In this above command myfile will be executed and run as processes. cat will not be executed. Instead, cat will be passed as argument to the program called myfile.

cat is not a program. It is just an inbuilt command. So, cat is not a file. Only myfile is a file.

Neither cat not myfile are stored on disk.