问题：

sudo apt-get update

Reading package lists... Done

E: Problem executing scripts APT::Update::Post-Invoke-Success

'if /usr/bin/test -w /var/cache/app-info -a -e /usr/bin/appstreamcli;

then appstreamcli refresh > /dev/null;

fi'

E: Sub-process returned an error code

解决方法如下：

sudo pkill -KILL appstreamcli

wget -P /tmp https://launchpad.net/ubuntu/+archive/primary/+files/appstream_0.9.4-1ubuntu1_amd64.deb https://launchpad.net/ubuntu/+archive/primary/+files/libappstream3_0.9.4-1ubuntu1_amd64.deb

sudo dpkg -i /tmp/appstream_0.9.4-1ubuntu1_amd64.deb /tmp/libappstream3_0.9.4-1ubuntu1_amd64.deb

执行完上述命令之后再次运行sudo apt-get update就不会再出现上面的错误