Diff Match and Patch 20121119
A set of Google-developed tool available in different programming languages, for performing Diff, Match and Patch operations for plain text
The diff tool works by comparing two pieces of plain text and then showing a list of differences between them, with both additions and removals.
The match tool takes a search string and using a fuzzy match algorithm it tries to find it in another block of text.
The patch tool is a little bit different, working by applying patches of text to another block of text, even if the text doesn't really match in between.