question on text processing

By emile 02 May 2003

given two near identical text files without endline characters with a differing substring of an arbitrary length and position in the latter file, is there a tool operable on a unix platform to generate a “patch file”, meaning a new file denoting which substrings to delete from the original and what to add to generate the new file, and then to later take such a diff file and apply it to the original to regenerate the edit? diff does this on a line by line basis and merge can rejoin them but i need a tool that analyses a string without endlines.