Ubuntu下添加系统根证书, 只要将证书(扩展名为crt)复制到**/usr/local/share/ca-certificates**文件夹然后运行update-ca-certificates即可。
添加证书：
$sudo cp 证书路径.crt /usr/local/share/ca-certificates
$sudo update-ca-certificates
删除证书：
$sudo rm -f /usr/local/share/ca-certificates/xinmu.crt
$sudo update-ca-certificates