最近在自己的arclinux上安装postgreSQL的时候出现错误如下：
error: postgresql-libs: signature from "Levente Polyak (anthraxx) <levente@leventepolyak.net>" is unknown trust
arclinux论坛搜到帖子[附]。
解决办法所删掉 /etc/pacman.d/gnupg/ ，由于文件夹下太多东西，不放心，移动到备份目录。
sudo mv /etc/pacman.d/gnupg/ /etc/pacman.d/gnupg.bk/
这个时候如果再安装，会报错说：
warning: Public keyring not found; have you run 'pacman-key --init'?
downloading required keys...
error: key "FC1B547C8D8172C8" could not be looked up remotely
error: required key missing from keyring
error: failed to commit transaction (unexpected error)
Errors occurred, no packages were upgraded.
需要更新pacman 的key。
pacman-key --init
pacman-key --populate archlinux
如果还是不行，就关掉校验吧。
sudo vim /etc/pacman.conf
把里面的SigLevel设置为 Never。
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