How to restore default fonts on Mavericks? I have deleted the Lucida Grande font from my system, and system bars and menus are full of weird characters. I cannot use my MBA properly. How can I restore system fonts without losing my data?
You can also copy the font from the recovery partition:

diskutil mount Recovery\ HD;hdiutil mount /Volumes/Recovery\ HD/com.apple.recovery.boot/BaseSystem.dmg;sudo cp /Volumes/OS\ X\ Base\ System/System/Library/Fonts/Base/LucidaGrande.ttc /System/Library/Fonts