权限提升
当你遇到这样的问题时
$ apt-get update
E: Could not open lock file /var/lib/apt/lists/lock - open (13: Permission denied)
E: Unable to lock directory /var/lib/apt/lists/
E: Could not open lock file /var/lib/dpkg/lock - open (13: Permission denied)
E: Unable to lock the administration directory (/var/lib/dpkg/), are you root?
那就可以直接使用sudo !!马上对前面的命令进行提权，而无需重新打一遍
