LibreOffice supports PDF conversion. What you need to do is to open the document in LibreOffice and click the Export as PDF… option under the file menu list. It’s good and simple to convert a single document but quite tedious if you have more files.
For batch conversion, we need to make use of the LibreOffice command in terminal.
1. Go to the directory which contains the source files.
2. Execute the following command to convert ALL files which ends with .odt into .pdf.
soffice --invisible --nologo --convert-to pdf *.odt
Eureka! 