ubnutu的任務欄都是在左側：
zhang@zhang-virtual-machine:~$ gsettings set com.canonical.Unity.Launcher launcher-position Bottom #底部（蘋果風格）
zhang@zhang-virtual-machine:~$ gsettings set com.canonical.Unity.Launcher launcher-position Left #左側（默認）
zhang@zhang-virtual-machine:~$ gsettings set com.canonical.Unity.Launcher launcher-position Right #右側
zhang@zhang-virtual-machine:~$ gsettings set com.canonical.Unity.Launcher launcher-position Top #頂部
