This may be seen as self-promotion - that's not totally wrong.  But I think this may also be useful to others and (as I acknowledge in the blog post) I'm quite pleased with the resultant script.

Over the past year and a half I've slowly developed a shell script that gives a concise summary of the state of TLS and HTTP(S) on a given website.  It looks like this:

    $ tlsdetails google.ca
    Using OpenSSL:  /usr/bin/openssl
    Expiry Date:    Oct 27 17:27:07 2019 GMT (78 days)
    Issuer:         Google Trust Services, CN
    TLS Versions:   tls1_3 tls1_2 tls1_1 tls1  (tried but unavailable: ssl3 ssl2 )
    HTTP Version:   2

I first started work on it after a couple embarrassing certificate expiries.  It then grew to check the Issuer, TLS versions, and more recently whether or not a site supports HTTP2.

(The pointer to the OpenSSL version is shown because the script will also run on Mac, and their version of 'openssl' is problematic at best.  That line is of course easy to remove if you don't like it.)

If you're interested, you can find the details here:

https://www.gilesorr.com/blog/tls-https-details.html

Any suggestions to improve the script would be most welcome.

--
Giles
https://www.gilesorr.com/
gilesorr@gmail.com