Free file comparison tools

text editor, improved version of Vi

alt=Screenshot of Multics Emacs|thumb|Multics Emacs is an example of early Emacs implementations Emacs (), originally named EMACS (an acronym for "Editor Macros"), is a family of text editors that are characterized by their extensibility. The manual for the most widely used variant, GNU Emacs, describes it as "the extensible, customizable, self-documenting, real-time display editor". Development of the first Emacs began in the mid-1970s, and work on GNU Emacs, directly descended from the original, is ongoing; its latest version is , released .

diff is a shell command that compares the content of files and reports differences. The term diff is also used to identify the output of the command and is used as a verb for running the command. To diff files, one runs diff to create a diff.

GNU version of the Emacs text editor

command line utility for Unix or a Unix-like operating systems

WinMerge is a free software tool for data comparison and merging of text-like files. It is useful for determining what has changed between versions, and then merging changes between versions.

GNOME visual diff and merge tool

comm is a shell command for comparing two files for common and distinct lines. It reads the files as lines of text and outputs text as three columns. The first two columns contain lines unique to the first and second file, respectively. The last column contains lines common to both. Columns are typically separated with the tab character. If the input text contains lines beginning with the separator character, the output columns can become ambiguous.

Xdelta is a command line tool for delta encoding, which stores or transmits the difference (deltas) between sequential data, instead of entire files. This is similar to diff and patch, except diff computes and shows the difference between two complete files, while patch is primarily designed for human-readable text files; Xdelta is designed for binary files and does not generate human readable output.

FreeFileSync is a program used for file synchronization. It is available on Windows, Linux and macOS. The project is backed by donations. Donors get access to a Donation Edition that contains a few additional features such as an auto-updater, parallel sync, portable version, and silent installation. FreeFileSync has received positive reviews. FreeFileSync is available free of charge for personal use; the official Windows installer requires the users to accept the terms of use, which state that for business use they are required to purchase a business edition version of the application.