FreeBSD12.2安装Nginx时报错 “You must upgrade the ports-mgmt/pkg port first.” 的解决方法

FreeBSD12.2在使用ports安装Nginx时报如下错误：

root@zFree001:/usr/ports/www/nginx # make install clean
===>  nginx-1.18.0_30,2 pkg(8) must be version 1.15.9 or greater, but you
have 1.15.6. You must upgrade the ports-mgmt/pkg port first.
*** Error code 1

Stop.
make: stopped in /usr/ports/www/nginx

解决办法如下：

#cd /usr/ports/ports-mgmt/pkg
#make deinstall reinstall

再次查看pkg版本信息

root@zFree001:/usr/ports/www/nginx # pkg -v
1.15.10

pkg版本是1.15.10就可以继续安装Nginx了。