Again, there are no special Linux or Windows license files.
The file license.dat is a normal text file and either is sent to you by mail or you can manage your licenses online
(https://www.ptc.com/appserver/lm/rsl/reconfig.jsp) yourself and create a license file suitable to the MAC address of your Linux host. If you are not entitled to manage your licenses online, someone else in your company should be. I think that he can entitle you or otherwise you will have to contact PTC licensing support.
https://support.ptc.com/appserver/cs/cust_care_case_logger/CustomerCareCaseLogger.jsp