????1???????汾??linux???????chroot????????????????passwd??????
????2??grub???????м???init=/bin/bash???????????????????????????????????????????????????ж?.
????3: grub???????м??? single????????????.
????4:?????????mount??????????/etc/passwd?е?root???????
????????:
????root:x:0:0:root:/root:/bin/bash???
????root::0:0:root:/root:/bin/bash(?????????x?????).
????????????????root?????????????????ssh????????????????????????????????????????