Looking for command line To-do app

I’m looking for a command line to-do app for UNIX-based systems. It must work on a Mac, though.

I don’t need no fancy text-based GUIs, just command line.

Each to-do must have the following fields:

• body of text;
• optional due date;
• a set of tags.

That’s it.

It’s so little that I though of writing it myself… I’m just curious to see if there is anything like it already.

BTW, I know about Remind, but although powerful, it’s a calendar application, not a to-do app.