XMM-Newton Science Analysis System: User Guide

2.4 Running SAS

There are currently three independent ways of operating SAS:

• Using the command line, as discussed in § 2.6.
• Using the SAS Graphical User Interface (GUI), as discussed in detail in § 3.
• From a Python session which can be started either from the command line or from a notebook, as dicussed in detail in § 2.9.

Starting with v.19, SAS includes a new infrastructure in Python which allows the execution of any SAS task either based on Python or not, from a pure Python session. Such interface aims at providing users with a bridge between SAS and Python, where a large amount of packages and tools are available from the user's community which might help in the process of analyzing XMM-Newton data. Simultaneously, new SAS Python-based tasks have been added which can be run from the command line, as any other SAS task.

SAS's main GUI can be accessed by typing sas on the command line. Also, almost every SAS task has its own specific GUI, which can be individually started by typing task_name -d.

Each type of interface has its own advantages and disadvantages, depending on the type of work the user has to do and the level of proficiency with SAS.

Intensive interactive work on single datasets could be done more efficiently using the GUI.

Beginners may find that the GUI is a good starting point since it allows to access and manage easily tasks with large number of parameters.

The Python interface, specially Jupyter Notebooks, could be preferible for users who are familiar with Python and want to work with SAS from there.

For the processing of large amounts of data, SAS tasks can be called from scripts written in any shell language -bash, tcsh, ksh- or using Python or Perl, with considerable efficiency.