On Monday 10 Mar 2014 16:20:25 Cao, Renzhi wrote: > Thanks Paul! > The reason why I copy /bin/* to /mnt/bin is my/mnt/bin is not exists. > I don't know what happens, it seems this is deleted when I try to fix my > problem. I will see if my system works well, if not, I will be back again > :) This is because everything in /bin was moved to /usr/bin, and /bin was supposed to become a symlink to /usr/bin. When you do this: ls -la / Do you see: /bin -> usr/bin /lib -> usr/lib /lib64 -> usr/lib /sbin -> usr/bin Hopefully, you will. If not, you need to do some more work. > Indeed, I learn a lot and now becomes more confident! I will tell my > adviser to do the backups for all the systems. If someday I lose the data, > I will share that "good news" to you immediately, and I believe that will > make a lot of fun for you and the community! :) Paul