Color diff that prints old and new lines with changed characters/words/blocks highlighted. It streams the GNU diff output line by line, coloring it on the fly.
If either file is a directory, it recursively searches for a corresponding file within that directory. GNU diff on Linux also supports file-vs-directory comparison by matching the filename within the directory, but without recursion.
If the second file is omitted, it recursively searches the current working directory for a corresponding file.
codiff is a standalone Perl script, just copy or download it and run. Don't forget chmod +x. Tested on Linux and macOS. Requires Algorithm::Diff, usually already installed.
Direct link:
curl -O https://raw.githubusercontent.com/rudojaksa/codiff/main/codiff