Binary package “ytnef-tools” in ubuntu bionic
ytnef decoder commandline tools
Yerase's TNEF Stream Reader allows you to decode application/ms-tnef
e-mail attachments, which are usually entitled "winmail.dat" and are
generally a file container format that is only readable by Microsoft
Outlook. Some TNEF streams also include RTF-formatted data.
.
These are the frontend programs for the libytnef library, which can be used
to decode TNEF attachments on the commandline.