I have some trouble using the terminal for the programs I have written, it doesn’t seem to find the files even though the terminal says they are there?
In this case, it’s because
fifteen is not a directory, it is in fact a file. When you ran
cd, it recognized that it was a file, and as such cannot be
cd'd into, so it gave the error message, “Not a directory.”
… yes Of Course… Now I get it . Thank you