[求助，急]这段代码是什么意思

3.清理、修复磁盘权限
cd /System/Library/Extensions
sudo chown -R root:wheel AppleAzaliaAudio.kext
sudo chmod -R 755 AppleAzaliaAudio.kext
sudo rm /System/Library/Extensions.*
kextload AppleAzaliaAudio.kext
kextcache -k /System/Library/Extensions/
diskutil repairpermissions /


急啊，在线等，多谢各位了