SAS Code can be copied from UNIX (HP-UX) to Linux and run without edits to the SAS Code. Of course, directory folder names will need to be updated.
No comes the discussion on SAS data files (data sets, indexes, and catalogs). Linux SAS 9 can read (read-only) SAS data files, but not SAS indexes or catalogs. If all you need is read access of plain SAS data sets with no indexes and no custom formats, then you can just copy the SAS data sets with any UNIX tool from one system to the other. SAS 9 will use the SAS CEDA feature to read these SAS data sets with the SAS 9 Linux version. SAS Help Center: Overview of Cross-Environment Data Access (CEDA)
If you need to be able to update the SAS data sets created on HP-UX and/or apply SAS Indexes and/or SAS custom formats, then you need to migrate these SAS data sets. There are several ways to do this. PROC MIGRATE seems to be the most popular tool (SUGI 28: PROC MIGRATE: How to Migrate Your Data and Know You?ve Done It Right! (sas.com)) You can also PROC CPORT and PROC CIMPORT your SAS data files.
Please let me know if you need more examples.