KDiff3 is a program that compares or merges two or three text input files or directories, shows the differences line by line and character by character (!), provides an automatic merge-facility and an integrated editor for comfortable solving of merge-conflicts, supports Unicode, UTF-8 and other codecs, autodetection via byte-order-mark "BOM" supports KIO on KDE (allows accessing ftp, sftp, fish, smb etc.), Printing of differences, Manual alignment of lines, Automatic merging of version control history ($Log$), and has an intuitive graphical user interface. Windows-Explorer integration Diff-Ext-for-KDiff3 - shell extension included in installer.....(free).....