oathtool

OATH one-time password tool. More information: https://www.nongnu.org/oath-toolkit/oathtool.1.html.

• Generate TOTP token (behaves like Google Authenticator):

oathtool --totp --base32 "secret"

• Generate a TOTP token for a specific time:

oathtool --totp --now "2004-02-29 16:21:42" --base32 "secret"

• Validate a TOTP token:

oathtool --totp --base32 "secret" "token"