I was working with certificates quite often and needed something similar. That's why I build https://github.com/pete911/certinfo. Among other things, it allows you to do what the above perl script does as well:

• get local certificates (with local chains - roots) certinfo -chains -pem-only <host>:443 > tmp_certs.pem
• remove duplicates (chain usually contains intermediate, or you can have multiple local chains) certinfo -no-duplicate -pem-only tmp_certs.pem > certs.pem