SlackBuildsOrg/office/etmtk

etmtk is an acronym for event and task manager.

In contrast to most calendar/todo applications, creating items (events,
tasks, and so forth) in etm does not require filling out fields in
a form. Instead, items are created as free-form text entries using a
simple, intuitive format and stored in plain text files.

Before running etm for the first time run this command as user: mkdir
~/.etm