原先贪图方便，用了ubuntu software center的包安装，后面发现有显示偏移的bug，只好重新安装最新版。

下载源码

解压编译安装

tar -xvf kdiff3-0.9.98.tar.gz
sudo apt-get install libqt4-dev
cd kdiff3-0.9.98/src-QT4/
qmake kdiff3.pro
make
sudo make install

if you don't have qt-devel.
sudo yum install qt-devel
sudo yum install qt4-devel

then qmake would be found under /usr/lib64/qt4/bin .

cd kdiff3-0.9.98/src-QT4/
qmake kdiff3.pro
make
sudo make install