Tool

DoubleKiller Pro finds duplicate or similar files by comparing any combination of name, size, date and content; optionally just a certain part or with a given tolerance. Files can be filtered by masks like *.dll, attributes or file size. When the scan is finished a list containing all duplicates found is displayed and you can
select the files to be deleted, moved to the Recycle Bin or a backup folder or replaced by shortcuts.

Automatic selection allows you to mark the oldest or biggest files of each set or all files in a certain directory for removal, for example. You can save scan sessions and load them any time later to review or continue your work. The
complete process of choosing directories, scanning for duplicates and
removing files can be automated via command line switches.

The user interface is multilingual and can be translated to your language
using freely downloadable language files. An optional help file provides first-step information, a complete reference, and usage examples.

Version: 2.1.0.104

New in v2.1:

• Supports scanning inside zip archives
• Catalog files: Catalogize CDs/DVDs/folders and scan the
  catalogues
• More...
  

See also a less-featured freeware version of DoubleKiller:
http://bigbangenterprises.de/en/doublekiller/.