You should be able to use 'netstat -a' within the OS in order to see all of the ports currently in use.  It won't tell you what process is using it, but if you are simply looking for open ports then this is a quick way to do it

There are different kernels but other than that you should be able to run the same ObjectScript code on both platforms and it will behalf identically.  If you are going to be doing file interactions, then I suggest using the %File library class which will make your code portable between Windows and UNIX file systems.  Likewise if you are calling out to other executables, you will need to instrument your code to call out appropriately based on your platform. 

I am assuming you want to create a tag-based CSP page as a quick and dirty way to through up some data in a table?  If so, the basic steps would be:

1. Load a JS library like https://www.tablefilter.com/ to make your filtering easy
2. Write out your <table> and <th> tags 
3. Create a <script language='cache' runat='server'> block to hold your ObjectScript which will fetch your result set 
4. Use %SQL.Statement to create and run the query and fetch the data
5. Iterate over the resultset, and write out a row of HTML for each row in the resultset using &html<>
6. End your </script> tag and then end your </table> tag

Hope that gets you rolling!