On the page at http://www.nongnu.org/oath-toolkit/oathtool.1.html
there are several examples. Copying/pasting these, at least from Firefox on a Mac, into a terminal fails for many of them, giving errors like "oathtool: hex decoding of secret key failed”.
This is because on the web page the dashes in arguments such as “—totp” are actually unicode minus signs, U+2212, instead of ASCII dash (0x2d) which is what the program expects.
PS: the same problem occurs in the email address for address@hidden
at the bottom of that page.