s3sync and s3cmd won't work if they're referenced via a symlink. For example, I copied the s3sync folder to /usr/local/s3sync, then created the following symlinks:

  /usr/local/bin/s3sync -> /usr/local/s3sync/s3sync.rb
  /usr/local/bin/s3cmd -> /usr/local/s3sync/s3cmd.rb

The problem is that the File.expand_path(File.dirname(__FILE__)) trick at the top of each file doesn't resolve symlinks. A solution is to replace it with Pathname.new(__FILE__).realpath.parent.to_s.

I'm attaching a patch.

  Scott