Could not open lock file /var/lib/apt/lists/lock - open (13: Permission denied)Ubuntu不能打开锁文件

背景：更换了Ubuntu系统语言后，apt-get 无法打开锁文件

问题：Could not open lock file /var/lib/apt/lists/lock - open (13: Permission denied)；E: Unable to lock directory /var/lib/apt/lists/
W: Problem unlinking the file /var/cache/apt/pkgcache.bin - RemoveCaches (13: Permission denied)
W: Problem unlinking the file /var/cache/apt/srcpkgcache.bin - RemoveCaches (13: Permission denied)

解决办法：

重新设置root权限

1.申请修改root

sudo passwd root

2.输入原密码，再敲两遍新密码，如下图。提示修改成功！

3.输入su，输入现有密码

su

4.成功！