dion@dion-Lenovo-ideapad-330S-15IKB:~$ apt install update
N: Ignoring file 'some-ppa.list.save.1' in directory '/etc/apt/sources.list.d/' as it has an invalid filename extension
N: Ignoring file 'some-ppa.list.save.4' in directory '/etc/apt/sources.list.d/' as it has an invalid filename extension
N: Ignoring file 'some-ppa.list.save.3' in directory '/etc/apt/sources.list.d/' as it has an invalid filename extension
N: Ignoring file 'some-ppa.list.save.2' in directory '/etc/apt/sources.list.d/' as it has an invalid filename extension
E: Type 'sudo' is not known on line 1 in source list /etc/apt/sources.list.d/docker.list
E: The list of sources could not be read.
E: Could not open lock file /var/lib/dpkg/lock-frontend - open (13: Permission denied)
E: Unable to acquire the dpkg frontend lock (/var/lib/dpkg/lock-frontend), are you root?
答案1
读出最后一行错误：
E: Unable to acquire the dpkg frontend lock (/var/lib/dpkg/lock-frontend), are you root?
你是 root 吗？不，你不是，你必须运行以下命令：
sudo apt install update
拥有 root / 管理权限。