There’s an old quip about solutions causing more problems: Some people, when confronted with a problem, think “I know, I’ll use regular expressions.” Now they have two problems.

Since I seldom need the functionality provided by oathgen (a complete HOTP/TOTP implementation), I typically use goathgen. Goathgen is a simple TOTP library and command line executable written in Go.

Oathgen is a command line HOTP and TOTP one-time password generator for BSD, Linux, Mac and Windows operating systems. The goal of oathgen is to be complete, standard and portable.