Once you have downloaded the specific SAS tar.gz archives for your operating system the installation is quite straightforward and platform independent
(see: http://xmm.esac.esa.int/sas/7.1.0/installation).
Choose a directory (e.g. /top_dir) to place the SAS software and unpack the tar.gz archives. The unpacking process will create a subdirectory named
xmmsas_YYYYMMDD_HHMM
which identifies uniquely each SAS release by the date (YYYYMMDD) and time (HHMM) of its production. For example, for the SAS 7.1.0 version, this is xmmsas_20070708_1801. In SAS terms, this is called the release manifest.
Move on to this subdirectory and execute the script
./configure_install
which if completed successfully, will produce two additional shell scripts within the same directory, named respectively setsas.sh for the Bourne/Bash/Korn shells and setsas.csh for the csh/tcsh shells. These are the scripts to be used later on to initialize the SAS environment.
The configure_install script makes some additional sanity checks on the installation environment as for example checks for the proper installation of the perl binary in the /usr/local/bin directory, which is required to run some SAS perl procedures.