git clone -b KDE/4.12 git://anongit.kde.org/marble ~/marble/sources
You can clone the sources to any directory on your system. If you have no preferences, choose ~/marble/sources as that is the directory we will use below.
Development happens both directly in the master branch and in feature branches like gsoc-2012-project-name. If you want to use the latest features or want to contribute to Marble, choose the master branch. The code inside these branches however is not as stable as the one in the release branches.
If stability is your main concern, choose the latest stable release branch, which can easily be recognized by the KDE/ prefix followed by a version number.
Here is a list of commonly used branch names:
Marble follows the common KDE release schedule. New features are developed in and merged to the master branch until the soft (hard) feature freeze. Afterwards a stabilizing period in master follows during which no new features and similar changes are committed to master. At the time of the first release candidate RC1 a new KDE/4.x branch is created from the current master branch. Afterwards the master branch is open for development again. The KDE/4.x are stable branches that never receive new features.
Don't worry too much about branches though! Thanks to git switching between branches is as easy as running e.g.
git checkout -b KDE/4.12 origin/KDE/4.12 and requires no Internet connection. No need to clone the repository again if you got the inital branch wrong above, just switch to it later.
mkdir -p ~/marble/build cd ~/marble/build cmake -DCMAKE_BUILD_TYPE=Debug -DQTONLY=FALSE -DCMAKE_INSTALL_PREFIX=/usr/local ~/marble/sources make sudo make install