异常报错

1: NOKEY
Extra Packages for Enterprise Linux 8 - x86_64                                                          0.0  B/s |   0  B     00:00
Curl error (37): Couldn't read a file:// file for file:///etc/pki/rpm-gpg/RPM-GPG-KEY-EPEL-8 [Couldn't open file /etc/pki/rpm-gpg/RPM-GPG-KEY-EPEL-8]
The downloaded packages were saved in cache until the next successful transaction.
You can remove cached packages by executing 'yum clean packages'

原因：RPM-GPG-KEY-EPEL-8 文件缺失，使用如下命令问题得以修复

修复方法：

cd /etc/pki/rpm-gpg/

wget https://archive.fedoraproject.org/pub/epel/RPM-GPG-KEY-EPEL-8

yum clean all && yum install ShellCheck -y