错误提示如下所示：



$ sudo apt update
Hit:1 http://security.ubuntu.com/ubuntu bionic-security InRelease
Hit:2 http://ca.archive.ubuntu.com/ubuntu bionic InRelease
Hit:3 http://ca.archive.ubuntu.com/ubuntu bionic-updates InRelease
Hit:4 http://ca.archive.ubuntu.com/ubuntu bionic-backports InRelease

(appstreamcli:15814): GLib-CRITICAL **: g_strchug: assertion 'string != NULL' failed

(appstreamcli:15814): GLib-CRITICAL **: g_strchomp: assertion 'string != NULL' failed

(appstreamcli:15814): GLib-CRITICAL **: g_strchug: assertion 'string != NULL' failed

(appstreamcli:15814): GLib-CRITICAL **: g_strchomp: assertion 'string != NULL' failed
AppStream cache update completed, but some metadata was ignored due to errors.
Reading package lists... Done
Building dependency tree       
Reading state information... Done
1675 packages can be upgraded. Run 'apt list --upgradable' to see them.


解决办法：



sudo sed -i -e 's/bionic/xenial/g' /etc/apt/sources.list


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