From KDE UserBase Wiki
  A tool to check, edit and merge differences between 2 or 3 files


  • 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.

The KDiff3 Handbook gives a detailed description of activities, in html form.