$ ls
Backgrounds                               blender-2.48a-linux-glibc236-py25-x86_64.tar.bz2  Desktop    Shared          untitled.blend1      VistaDesktop
blender-2.48a-linux-glibc236-py25-x86_64  Documents  untitled.blend  VirtualBox_Paragon1  WinXP-justparagon
$ mv Documents Local Documents
mv: cannot stat `Local': No such file or directory
$ mv Documents "Local Documents"
mv: cannot stat `Documents': No such file or directory
$ ls
Backgrounds                               blender-2.48a-linux-glibc236-py25-x86_64.tar.bz2  Desktop  untitled.blend   VirtualBox_Paragon1  WinXP-justparagon
blender-2.48a-linux-glibc236-py25-x86_64  Shared   untitled.blend1  VistaDesktop