FileSync!

Beyond Compare allows you to compare files and folders. By using simple, powerful commands you can focus on the differences you're interested in and ignore those you're not. You can then merge the changes, synchronize your files, and generate reports for your records.

SyncBack is a backup and file synchronization software that allows backing up and synchronizing files to the same or different drives, to different media (CD, DVD, Flash, zip), or to a remote server.There are three versions of SyncBack available: SyncBack Freeware, SyncBackSE (shareware) or SyncBackPro (shareware).

KDiff3 is a file and directory diff and merge tool which compares and merges two or three text input files or directories, shows the differences line by line and character by character, provides an automatic merge-facility, has an editor for comfortable solving of merge-conflicts, provides networktransparency via KIO, has options to highlight or hide changes in white-space or comments, supports Unicode, UTF-8 and other file encodings, prints differences, supports version control keyword and history merging. »

SyncToy is a free PowerToy designed by Microsoft, that provides an easy to use graphical user interface that can automatically synchronize local or network files and folders, but not WebDAV-, "Windows Mobile" files or folders and no triangle-sync as only Allway Sync, Synkron, SyncLess or GoodSync can do. No VSS-support, not portable. SyncToy can manage multiple sets of folders at the same time; it can combine files from two folders in one case, and mimic renames and deletes in another case. Unlike other applications, SyncToy actually keeps track of renames to files and will make sure those changes get carried over to the synchronized folder. »

Grsync is a rsync gui, a graphical user interface for the rsync file synchronization and backup tool. It works on linux, solaris, windows, mac os x and maemo. It uses the gtk libraries and can work under the gnome desktop.

WinMerge 2011 series is a fork of the original WinMerge application that compiles without ATL/MFC dependencies to enable zero-budget developers to build WinMerge from sources using Visual C++ Express editions.

Allway Sync is a file and folder synchronization software for Windows.

Back up your data and synchronize PCs, Macs, servers, notebooks, and online storage space.

DiffMerge is a graphical file comparison program for Windows, Mac OS X and Unix, published by SourceGear.* Integrates with Windows Explorer; adds a shortcut to the context menu.* Compatible with different character encodings, including Unicode support.* Performs a side-by-side comparison of two folders.* Supports comparison of three files.

Merge is the visual file comparison (diff), merging and folder synchronization application from Araxis. Use it to compare and merge source code, web pages, XML and other text files with native application performance. Directly open and compare the text from Microsoft Office (Word and Excel), OpenDocument, PDF and RTF files. Compare images and binary files. Synchronize folders. Perform code reviews and audits. Work with folder hierarchies containing thousands of files. Merge integrates with many SCM (version control) systems and other applications. »

FileMerge is part of Xcode .