Diffuse

Meld is a visual diff and merge tool. You can compare two or three files and edit them in place (diffs update dynamically). You can compare two or three folders …

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 …

KDE GUI for diff. Kompare allows the user to view the differences between two text files, merge these and recursively compare directories.

tkdiff is a graphical diff viewer based on the Tk framework. It is capable of inter-operating with source-control systems like CVS and Subversion to show differences between a local copy …

GNU Diffutils is a package of several programs related to finding differences between files.

xxdiff is a QT based graphical file and directories comparator and merge tool. It provides comparing two files, three files.