You are using Znuny with Configuration Management DataBase (CMDB) as a data store for hardware and software and you want to export this data for reuse?
Depending on your OS and installation way of OTRS/Znuny there are different ways.
Ubuntu and Debian based Znuny installs
for deb package and for debian based source installs you can execute:
sudo -u otrs /opt/otrs/bin/otrs.Console.pl Admin::ITSM::ImportExport::Export