No-install Unix Tools for Windows is a collection of 18 of the most useful Cygwin tools packaged into a single 1.1MB (floppy sized) EXE file that runs without any installation process. Simply running the executable instantly creates a Unix environment for Windows, without making any persistent changes to the underlying system. It includes bash, less, gzip, grep, find, df, du, ls, cat, cp, mv, ps, rmdir, mkdir, rm, pwd, and tar.
The bitap library is a clean implementation of regular expression (regex/grep) string matching using the bitap algorithm. Approximate (a.k.a. fuzzy) matching is allowed. This is the same algorithm as the one used in Glimpse and agrep, but it is much more complete with regard to regular expression syntax, and is much cleaner.
similarity-utils is a set of two programs to give a quantitative measure of how similar two files are, on a scale 0 to 1. similarity_by_diff measures the number of difference lines reported by diff(1), while similarity_by_zlib tries compressing the two files, both separately and together, and comparing the results.