Shows x509 certificate in  areadable format (-noout to not show certificate (PKCS1 DER encoded))
{{{
#!sh
$ openssl x509 -noout -text -in pemFile.pem
}}}

Get the certificate of a data node and return its expired dates
{{{
#!sh
$ openssl s_client -connect pcmdi7.llnl.gov:443 </dev/null 2>/dev/null|openssl x509 -noout -dates
notBefore=Oct 16 00:00:00 2013 GMT
notAfter=Oct 27 23:59:59 2014 GMT
}}}