KDiff3

KDiff3 compares and merges two or three input files or folders. It shows differences line by line and character by character, and offers automatic merge with an integrated editor to resolve conflicts comfortably.

Options let the user highlight or hide differences in whitespace or comments. KDiff3 supports Unicode, UTF-8 and other file encodings, can print differences, and provides network transparency through KIO. It is often used as the merge tool of version control systems.

KDiff3 is a KDE application, free and open source under the GPL-2.0 licence, available for Linux, Windows and macOS.