摘要：
Ubuntu的sudoapt getupdate出现错误：E:ProblemexecutionscriptsAPT:：Update:Post-Invoke-Success'if/usr/bin/test-w/var/cache/app-info a-E/usr/bin/appstreamcli；thenapstreamclirefresh˃/dev/null；fi'E：子进程
Ubuntu用sudo apt-get update出错：
- 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：
先remove libappstream3
- sudo apt-get remove libappstream3
- or
- sudo apt remove libappstream3
sudo apt-get update
参考：
https://askubuntu.com/questions/942895/e-problem-executing-scripts-aptupdatepost-invoke-success