ebook2pdf Letter-1.odt
And the output will be something like this:
Copyright© 2016-2018 ArdeshirV@protonmail.com, Licensed under GPLv3+
Documents to PDF Convertor
ebook2pdf Letter-1.odt
Copyright© 2016-2018 ArdeshirV@protonmail.com, Licensed under GPLv3+
Documents to PDF Convertor
https://github.com/ArdeshirV/ebook2pdf
GNU General Public License v3.0