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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
执行以下命令 解决：
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
再执行： sudo apt-get update