SAS Topics: Using SAS on Unix

1. Introduction
   
   
2. Using SAS With Your IFS Home Directory
   
   
3. Three Modes for Running SAS



1. Noninteractive Mode
   1. A Sample SAS Session in Noninteractive Mode
   2. Example of Running SAS in Noninteractive Mode
   
   
2. Interactive Line Mode
   1. Example of Running SAS in Interactive Line Mode
   
   
3. Display Manager Mode
   1. Starting the X Window System Software
   2. Connecting to the Statistics Service
   3. Setting the Display to Your Local Machine
   4. Starting SAS
   5. The Basic Windows
      1. Program Editor
      2. Log
      3. Output


4. A "Short" List of SAS Manuals
   
   
5. Getting Help With SAS
   
   
   1. Consulting
   
   
   
   2. Documentation

SAS is one of the statistical programs provided through the Statistics Service. SAS has a variety of routines that make it a powerful and flexible tool not only for statistical analysis, but also for data management, graphical displays, and many other types of tasks.

Many users of SAS will be using SAS from their IFS (Institutional File System) home directory. For example, the IFS home directory for an individual with the uniqname bjensen would be

There is a minor bug in SAS6.09 when used with a home directory which resides in IFS/AFS. Some users may receive a warning about failing to read the SASUSER.PROFILE.CATALOG. This is being investigated by SAS Technical Support. A workaround for the time being is to do the following when invoking SAS:

You would type the following commands at the Unix prompt, where $user would be your uniqname:

mkdir /tmp/$user

sas -sasuser /tmp/$user

For example, bjensen could invoke SAS with the following commands:

mkdir /tmp/bjensen

sas -sasuser /tmp/bjensen

Other options or a command file could also be specified when invoking SAS, as discussed below.

There are many ways to run SAS on Unix. This document will discuss three modes for running SAS:

Noninteractive mode

Interactive line mode

Display manager mode

Noninteractive mode is one way to run SAS on Unix that does not require a special connection (like Ethernet), or a graphical interface. If you are used to connecting to MTS via PROCOMM PLUS, or VersaTerm, or PCTIE, this mode will be very easy to use. The advantage of using noninteractive mode is that it is widely accessible: in this mode, you can use SAS from anywhere that you can connect (at home, or at the office) and you can use it with only a modem connection. The disadvantage is that high resolution graphics are not possible when using this mode of accessing SAS.

SAS in noninteractive mode is run by creating a command file and issuing the SAS command from within Unix as shown below:

Note that "sas" is given in lower case letters. This is to conform to the Unix SAS convention. If, for example, your command file were called test.sas, the command to run it would be:

A list of options may be given to customize your SAS output or your SAS session. For example, if you wanted your SAS output to be a width that is easily readable from the terminal (i.e. linesize=72), and you did not want the date to be printed on each page of output, you might run SAS with the options shown below.

When SAS is run in noninteractive mode, there will be no messages, or other indication that the program is running. You will simply notice that the Unix prompt will be gone for a period of time that will vary according to the size of the program that you are running, and the number of other users and the size of their jobs. When your SAS job has completed, you will again see the Unix prompt, and will be able to do other tasks.

If you wish to run SAS in the background, and be able to do other tasks while SAS is running, you may give the command:

SAS in noninteractive mode usually creates two files when it is run. The first is a log file that contains a listing of your SAS commands, along with any notes or errors from SAS. This file is essential for troubleshooting, and is where you would look if you have difficulty with a particular program that you are running. If your command file were named test.sas, as in the example above, the log file would be called test.log. If you wanted to view the contents of test.log, you could issue the Unix command:

This will display the contents of test.log one screen at a time so that you may browse its contents. When you want the screen to advance, simply press the space bar to advance the file display by one screen, or press Return to advance the file display by one line. If you wish to stop the screen display at any point, type "q" and you will be returned to Unix.

Depending on the commands that you have given SAS, it may also create an output file. This file will contain the output from any procedures that you have run in SAS. If your command file were called test.sas, the output file would be called test.lst. To view the contents of the file test.lst, give the following Unix command:

For this example, we will assume that you have created a command file called test.sas. The command file shown below tells SAS to create a temporary data set called test, containing the variables SUBJECT (which is a character, or string variable, as indicated by the $ sign after the variable SUBJECT), AGE, GROUP AND SBP (systolic blood pressure). A listing of the data set test is then obtained from SAS by using the SAS procedure, proc print. A listing of test.sas is shown below:

This command file could be run on Unix SAS and the output viewed by giving the following sequence of commands:

The command "ls -l test*" is a Unix command that is run when the SAS run is completed. It tells Unix to give a listing of all files that begin with "test" and have any ending (the wild card "*" is used). This will let you know if your log and output files have been created. The log and output files are then viewed with the "more" command. In general, it is wise to check which files have been created after a SAS run. If your commands were not completely executed because of errors in the command file, an output (.lst) file may not have been created. However, the log (.log) file would have been created in any case. This file may be browsed using the "more" command to see where the error occurred.

If your raw data were in a separate file, you could create a command file similar to the one shown below. The Unix command "more" is used to view the command file test2.sas. Note that the infile statement points to the raw data file test.dat, which is listed after the command file, again, using the Unix "more" command.

The command file test2.sas could be run in Unix by issuing the following commands:

For more information about running SAS in noninteractive mode, see SAS Companion for Unix Environments: Language, Version 6, First Edition.

Interactive line mode is another method for running SAS if you do not have a terminal screen that will support graphics output. It may also be used on a graphics terminal screen, if you do not desire to run SAS in display manager mode. This method of running SAS allows you to submit command files via the %include command, or to enter commands manually, one line at a time. In interactive line mode, the SAS log and output will all appear on the screen, one line at a time. To invoke SAS in interactive mode, you may issue the Unix command:

The -nodms option states that you do not want to run SAS in data manager mode. If you wanted to run your command file, test.sas via interactive line mode, you could issue the following command in Unix:

The command "sas -nodms" invokes SAS in interactive line mode. Once SAS is invoked in this mode, you will see some information from SAS on your screen. Then, you will see a linenumber prompt from SAS:

at this point, you may enter SAS commands one line at a time, or submit a command file by using the %include statement. For example to submit test.sas, you would type

after a linenumber prompt.

When you are finished with your SAS session, you may exit SAS by typing the command "endsas;" at a linenumber prompt.

For more information about running SAS in interactive line mode, see SAS Companion for Unix Environments: Language, Version 6, First Edition.

You can run SAS in display manager mode if you have a terminal that is capable of displaying X Window System output. This mode of running SAS allows you to have windows with pull down menus, to have high quaCgraphics, and to scroll through your commands, log and output. It is much more memory intensive than either of the previous two methods for running SAS, and is not recommended if you have large jobs to run.

You may use SAS with the X Window System and Display Manager Mode if your local machine is an X terminal, or a Unix workstation, or if you have X server software on your PC.

Some examples of X server software for the PC are Xoftware by AGE Logic, or eXceed, by Hummingbird. In order to use X Window System displays on your local computer, it will be necessary for you to be connected to the network via Ethernet, or some other method that is capable of transmitting large amounts of data very quickly, and producing graphics displays on your local machine.

To run SAS in Display Manager Mode, with the X Window System, there are four steps involved:

1. Start the X Window System server software
2. Connect to the Statistics Service
3. Set the display to be sent to your local machine
4. Start SAS

Display Manager Mode for Macintosh

To run SAS in Display Manager Mode, Mac OS X users should:

1)  Install X11 for Mac OS X (a custom install from your OS X software discs), if it is not already installed.
2)  Start X11 (installed under Applications>Utilities>X11)
3)  In X11, open a new Terminal window from the Applications pulldown menu.  (This terminal window must be opened with X11, and not with the simpler "Terminal" program also installed in the Utilities folder.)
4)  At the % prompt, type
        %  ssh -X uniquename@scs.itd.umich.edu
        %  password
          %  sas

For a good, concise explanation of X11, refer to http://www.scl.utah.edu/computers/mac/help/x11/.

Starting the X Window System Software

Whatever local machine you are using, you must first start up your local X server software. If you are using a Unix machine locally, the X server software may be already activated when you log in. If not, ask someone how to start it on your machine. If you are using a PC with Windows, you will want to start your X server software (e.g. double click on the Xoftware or eXceed icon).

Next, you must telnet to the Statistics Service. This can be done with a telnet command (from a Unix workstation), or may be done with the LAN WorkPlace for DOS Host Presenter software from a PC with Windows. (Open Windows, double click on the LAN WorkPlace icon, and once it is open, double click on the Host Presenter icon, then open the host "stat.itd.umich.edu").

Once you are connected to the Statistics Service, you must tell the machine to which you are connected that you wish to have your SAS display sent to your local machine. This can be done by giving the following command in Unix:

For example, if your local machine is named grumpy.cscar.umich.edu, you would issue the following commands:

Once you have done the previous steps, you can invoke SAS with the following command in Unix:

You may give options to customize your SAS session when you invoke SAS. If you have everything set up properly, SAS will begin executing, and after a few seconds you will see three windows appear on your screen:

• Program Editor
• Log
• Output

The Program Editor window is actually an editor that can be used to create and modify SAS command files. The Program Editor window has several pull-down menus along the top of it. They are File, Edit, View, Locals, Globals and Help.

The File menu is used for opening, saving and printing files (text files only, not SAS data sets!). It is also the menu used to Exit from SAS. The Edit menu can be used to clear the Program Editor, or to do other editing tasks. The Locals menu is used to submit commands and to recall previously submitted commands. The Globals menu is used to get around from window to window, and also to execute other SAS procedures, like SAS Assist.

When you are in the Program Editor, you may edit and change files, or create new files. After your command file is set up the way you want it to be, simply go to the Locals menu and choose Submit. This will send the commands in the Program Editor to SAS to be processed.

The Log window contains any messages that the Unix administrator wants you to read, and a log of all your commands, and any error messages from SAS.

After submitting a SAS command file, it is always wise to check the Log for any possible errors that may have occurred. Even if there are no problems with your program, there is valuable information in the Log, such as the number of observations and number of variables in any data set that you may have created. It is always good to check these things to make sure that the data set is as you expected it to be.

The Output window contains the output from any SAS commands that you have submitted. You can control the appearance of the output by using SAS options, like linesize and pagesize. Once you have checked your output to be sure that it looks correct, you may wish to save your output to a file. The file may then be printed at a later time.

A very large library of SAS manuals is available for ordering from the SAS Institute. Some of these manuals are also available from Photo and Campus Services (764-9216) in the basement of the LSA Building. In addition to those listed below are many manuals for specific SAS products, as well as technical reports. A full listing of publications is in the SAS Publicatons Catalog, available from SAS Institute. Their phone number is 919-677-8000. Ask for Book Sales. An annotated list of some SAS manuals is given below.

SAS Language and Procedures: Introduction, Version 6, First Edition. This small but very useful guide provides a good basic introduction to SAS, and gives a tutorial. It is highly recommended for new SAS users.

SAS Language and Procedures: Usage, Version 6, First Edition and
SAS Language and Procedures: Usage II, Version 6, First Edition. These two thick volumes are very useful for new SAS users, since they give many examples of how to do specific tasks.

SAS Language: Reference, Version 6, First Edition. This is the basic reference guide for SAS, and is essential for serious users of SAS. It provides the most complete information on the base SAS software, and includes information on reading external files, formatting data, data transformations and merging data sets, among other things.

SAS Procedures Guide, Version 6, First Edition. This manual provides syntax for the base SAS procedures, including proc contents, proc copy, proc freq, proc means, and many others.

SAS Companion for Unix Environments: Language, version 6, First Edition, 1993. This guide is essential for Unix SAS users, and you should have access to it when using SAS on Unix. It gives information on how to access external files, how to use SAS with data sets from other statistical programs, such as OSIRIS, BMDP and SPSS, and how to read and create SAS transport files on the Unix platform, along with much other useful information.

SAS Companion for Unix Environments: User Interfaces, Version 6, First Edition, 1993. This guide gives specific information on customizing your SAS interface for the specific environment from which you are running SAS. This guide is appropriate for more advanced Unix and SAS users.

SAS Applications Guide, 1987 Edition. This guide is extremely useful for anyone wanting to do data management tasks using SAS. It gives practical examples for recoding data, merging data sets, reading hierarchical data, and reshaping data to make variables into observations and to make observations into variables. It carries a lot of information in a small package.

SAS System for Elementary Statistical Analysis, 1987. This small volume gives step-by-step illustrations on how to do elementary statistical analysis using SAS. It covers univariate statistics, t-tests, anova, regression and simple plots, among other things. Highly recommended for new users of SAS for statistics.

SAS/STAT User's Guide, Volumes 1 and 2, Version 6, Fourth Edition. These guides are essential for running SAS to do traditional types of statistical analysis, including ols regression, anova, factor analysis, logistic regression, nonparametric tests, etc. They give the syntax, options and examples of each procedure.

SAS Technical Report P-229. SAS/STAT Software: Changes and Enhancements, Release 6.07, 1992. This manual updates the SAS/STAT User's Guides to include enhancements to various statistical procedures. Information is also included on some new procedures, including Proc Mixed, a procedure for analyzing mixed models anova (unbalanced random effects models) and models with various covariance structures. Proc Phreg is also included for Cox model survival analysis.

SAS/ETS User's Guide, Version 6, Second Edition. This guide gives information on the ETS (Econometric Time Series) procedure. It includes information on arima models, systems of linear equations, and systems of nonlinear equations, as well as time series cross-sectional studies.

SAS/ETS Software: Applications, Guide 1 and Guide 2, version 6, first edition. These two guides give practical examples of how to carry out various types of models using ETS (Econometric Time Series). Very useful for those doing econometric modeling.

SAS/IML Software: Usage and Reference, Version 6, First Edition. This guide documents the SAS IML (Interactive Matrix Language) procedure. This extremely powerful procedure allows users to manipulate matrices, rather than working only with individual variables. This facility allows users to build their own statistical procedures, do simulations, etc.

SAS Technical Report P-230, SAS/IML Software: Changes and Enhancements, Release 6.07. This volume documents updates to IML, including new built-in functions to do numerical integration, and solve ordinary differential equations. It also documents the library of built-in modules written in the IML language.

SAS System for Linear Models, 3rd Edition, 1991. This handy guide gives explanations and examples for working with linear models (regression and anova) using SAS.

SAS Graph Software: Introduction, Version 6, First Edition, 1990. This small introductory guide is very useful for new users of SAS Graph. It gives information on how to produce simple graphs, and send the output to the screen, a printer or a file.

SAS/Graph Software: Usage, Version 6, First Edition. This manual provides illustrations of many common graphing tasks. A good manual for non-experienced SAS Graph users.

SAS/GRAPH Software: Reference, Volumes 1 and 2, Version 6, first edition, 1990. These two thick volumes give the syntax for SAS Graph and are the most complete resource for this procedure. Volume 1 gives information on how to produce titles, footnotes, legends, annotation in graphs, etc. Volume 2 gives information on specific procedures. These are only recommended for serious SAS Graph users.

SAS Guide to Macro Processing, Version 6, Second Edition. This guide gives information on how to do macro processing using SAS. It is essential for anyone wishing to set up macros to do repeated or complex procedures in SAS.

CSCAR consultants provide technical assistance on the use of a variety of statistical software packages, including SAS. They are also available to assist researchers with statistical methodology issues. The CSCAR consultants can be reached via email, telephone or personal visit. All persons engaged in scientific research, including staff, faculty and graduate students, are are encouraged to contact the CSCAR with their questions!

Additionally, the CSCAR offers the informal statistical workshop series, "Continuing Training to Facilitate Quantitative Research." Sessions covering the use of statistical software packages, including SAS, and seminars on the use of statistics in research and industry are offered.

ITCS consultants provide general computer assistance at 764-HELP; School of Education and Angell Hall Courtyard computing sites; and via e-mail (online.consulting@umich.edu). For more information on consulting please visit                                         http://www.itd.umich.edu/help/over.consultant.html.  Additional information about documentation, workshops, and other services can be found at http://www.itcs.umich.edu. 

ITCS no longer provides SAS documentation, but information on general ITCS documentation can be found at this page: http://www.itcs.umich.edu/itcsdocs/