SlackBuildsOrg/office/odt2txt

A simple converter from OpenDocument Text to plain text odt2txt is
a command-line tool which extracts the text out of OpenDocument Texts
produced by OpenOffice.org, StarOffice, KOffice and others.

odt2txt can also extract text from some file formats similar to OpenDocument
Text, such as OpenOffice.org XML (*.sxw), which was used by OpenOffice.org
version 1.x and older StarOffice versions. To a lesser extend, odt2txt
may be useful to extract content from OpenDocument spreadsheets (*.ods)
and OpenDocument presentations (*.odp).