Concatenate FILE(s) to standard output. With no FILE, or when FILE is -, read standard input.
Outputs the contents of one or more files or standard inputs. The default output is to the standard output, which is equivalent to displaying them. Use '-' for standard input, so you can enter the content manually. You can use angle brackets to output or append to a file, please search 'bash angle brackets' for more.
'-' means standard input. Can only be used once. Must be at the end of the file list.