Well, you'll have to install XPP on Linux using the Linux installer ISO, obviously. But after that, you can bring over your XPP data from Windows and it will be find on Linux. That includes your L, K and X libraries in sd_liz, fonts in your xz/psres fonts, all your image libraries, and all JOBs/DIVs under all your job handles. Because of path differences, you'll have to do obvious configuration work on Linux for the paths to your job handles, for example, or the paths to graphic libraries in your Graphics Configuration (_im_config.sde) spec, etc. And be sure to run makepsres on your xz/psres folder afer copying it over so your PSres.upr file reflects the Linux pathing. XPP automatically applies byte-swapping so Linux can compose DIVs created on Windows and vice-versa.

I would recommend caution copying Lsyslib over. If you haven't modified anything on the Windows side, then just run with the Linux-delivered Lsyslib. If you have made changes, I'd recommend merging them into the Linux Lsyslib rather than stomping on it with Windows Lsyslib. But that's just me. I've been QA'ing XPP for 35 years and I just do not mess with our Lsyslib on either platform.

Thank you Shawn for the detail information. It is really helpful.

I would like to add some little notes to the excellent advise that Shawn has given you.
As far as I know the perl that gets dilivered with the Linux version of XPP is different from the Windows version. It will be the same version but the source is different. So it will most probably not come with the same perl modules.
There is a very small chance that if you have done some extensive perl programming around your current XPP system that somebody had used a perl module that is not available on the Linux perl. And it is most probably not the case for your system. But bettter be safe then sorry.
If this happens to be the case, then it is not a disaster. You will just have to install the missiing module(s?) manually using the perl mcpan command.

But as I said the changes that you run into this problem are very slim.

As of XPP 9.7, we now make "Strawberry" Perl from same CPAN Perl source used for Linux, so that should not be a problem. But perl modules added in earlier XPP versions would certainly need testing if moved from Windows platform to Linux running XPP 9.7 or later.

Thank you Bart for your input.