UNIX stores files as sequences of bytes and doesn’t impose any structure on them. Therefore, text files (those written using an editor) are strings of characters with lines delimited by the line feed, or new line, character. On the other hand, binary files (those containing executable code generated by a compiler or assembler) are sequences of binary digits grouped into words as they will appear in memory during execution of the program. Therefore, the structure of files is controlled by the programs that use them, not by the system.