曾经遇到过几次更新 ports 时出现如下的错误信息
# portsnap fetch update
Fetching 4 metadata patches... done.
Applying metadata patches... done.
Fetching 5 metadata files... gunzip: (stdin): unexpected end of file
metadata is corrupt.
这种情况只要清理一下 ports 缓存就能解决
# rm /var/db/portsnap/tag