12 hours for a complete KDE compilation is rather fast.
On my Pentium II 266 MHz, it takes a day or 2 for a base KDE, no games, no education packages etc...
Unfortunatly, gcc isn't the fastest compiler.
And what command did you type? What do you mean with that?
Do you want to start this new KDE version?
Tip: check out the tutorials on
http://developer.kde.org/