KDiff3
- Compares and merges 2 or 3 files or directories. The file diff shows changes within each line. For Unix and for Windows. Source available under GPL.
- http://kdiff3.sourceforge.net

Advanced CheckSum Verifier
- Verify the integrity of files, by using the CRC32 or MD5 checksum calculation algorithms. Checksums may be used for revealing the damaged files or compare two files for identity. [Windows 95/98/Me/NT/2000/XP].
- http://www.irnis.net/

1-2-3 Synchronize and Backup
- An easy tool for synchronizing and backing up files and folders.
- http://www.123syncbackup.com/

fsum
- Free file checksum generation and verification utility. Supports .MD5 and .SFV file formats.
- http://www.slavasoft.com/fsum/

Unison
- File synchronization tool that allows two replicas of a collection of files. Directories to be stored on different hosts (or different disks on the same host), modified separately, and then brought up to date by propagating the changes in each replica to
- http://www.cis.upenn.edu/~bcpierce/unison/

One-on-One
- Utility to compare one folder or volume with another supports both MAC and PCs.
- http://www.image-ination.com/oneonone/

Generic Diff Format
- Specification of GDIFF, a generic file format for representing the differences between two files, from Marimba to the W3C.
- http://www.w3.org/TR/NOTE-gdiff-19970901.html

DateWise FileCompare
- Patented comparison technique that automatically recognizes a file with embedded tokens, and reporting differences between the files and embedded tokens separately. The utility is available in both EBCDIC and ASCII versions for almost every platform.
- http://www.datewise.com/mt/

Darwin Open Systems
- Including Java diff source code, idiff, mgdiff, and spiff Unix tar.gz downloads.
- http://www.darwinsys.com/freeware/

File SyncForce
- Perform file synchronization between PCs, laptops, hard drives, and client and server networks. Automatically detect which files have changed within a given directory and synchronize those changes to a destination directory, and log the files that have be
- http://www.objectforce.com/file_sync.htm

Diasoft Corp.
- File Replication Pro, is a secure TCP/IP based replication solution, automatic real-time or scheduled replication across LANs, WANs, Internet and firewalls. [Win 95/98/ME/NT/2000/UNIX/LINUX/MAC]
- http://www.filereplicationpro.com/

SoftInterface, Inc.
- WordDocDiff compares two MSWord/Text files side by side. Complements FindInFilesX and CompareFilesX.
- http://www.softinterface.com/

Guiffy Software
- Shareware text file compare/smart-merge tool with a 1.2 Java/Swing GUI. For all Java-enabled platforms.
- http://www.guiffy.com

ComponentSoftware
- CSDiff : text, HTML, or MSWord file difference analysis tool, for Windows 95/98/NT. HtmlDiff : online CGI program to compare any two text files on the Web. Each free.
- http://www.componentsoftware.com/

Wtkdiff
- "Weak" tkdiff, or "Wayne's" tkdiff, an attempt at a minimal version of John Klassa's tkdiff processor. Tcl/Tk source code.
- http://sheol.org/throopw/wtkdiff.html