A program that displays every character in a file in hexadecimal notation. Also called a "binary editor," hex editors are used extensively in program development to view the actual content of a file, as well as to view files in old formats that are not recognized by today's applications. Regular text editors display alphanumeric text and do not normally display characters below ASCII 32 or above ASCII 127. When it is necessary to inspect a file or a fragment of data for its true contents, only a hex editor will suffice. See hex, text editor and source code editor.