SAS has supported UNIX systems since at least version 6.09 (that's when I started working with SAS in 1998).
The current version is 9.4M7, and all versions in between were available at least on Solaris, HP-UX and AIX. I think Linux was a later addition, but it is now the most-used UNIX platform for SAS.
You need to take care which operating system versions are supported for a given SAS release. Older versions of SAS can work on newer OS releases, but that is not guaranteed, and later SAS versions will usually not work on older OS versions, as capabilities are used that were not present in the earlier OS.