Copies a file.
filecopy <file1> <file2>
Copies file <file1> to file <file2>.
If <file2> already exists, it is overwritten. <file1> and <file2> must not be same.
If the file is deleted successfully, the system variable "result" is set to 0. Otherwise, "result" is set to non-zero.
filecopy 'test.dat' 'test2.dat'