Most of the reason I am posting this is to provide some Google juice to people who are searching for this information. I am a big fan of Yubico and use Yubikeys, but the documentation is pretty poor. This is one example via a post from last year.
I recently switched to Linux Mint. A
few weeks later it became time to change the PIN on my Yubikey. I added
the Yubico apt repository and installed the
yubikey-piv-manager as per
here. Alas, it did
not recognize my Yubikey and instead displayed the error:
No Yubikey found. please insert a PIV enabled Yubikey…
It was a bit of a mystery because
dmesg output clearly showed the Yubi being inserted,
so I knew the OS could see it. Turns out you also need to install the
opensc package to enable smart card support in Linux Mint. It doesn’t
come installed nor does the Yubi repository include it as a dependency.