SAS System Libraries

The WORK library is the temporary (scratch) library that is automatically defined by SAS at the beginning of each SAS session. The WORK library stores two types of temporary files: those that you create and those that are created internally by SAS as part of normal processing. Typically, the WORK library is deleted at the end of each SAS session if the session terminates normally.

To store or retrieve SAS files in the WORK library, specify a one-level name in your SAS program statements. The libref WORK is automatically assigned to these files as a system default unless you have assigned the USER libref. The following examples contain valid names for SAS data sets stored in the WORK library:

While the WORK library is designed to hold temporary files used during the current SAS session, the USER library is designed to hold files after the SAS session is over. If you associate the libref USER with a SAS library, use a one-level name to create and access files that are not deleted at the end of your SAS session. When SAS encounters a one-level filename, it looks first in the USER library, if it has been defined, and then it looks in WORK. If you want to place a file in the USER library, so that it is not deleted after your SAS session is over, any single-level file goes there by default. At that point, if you want to create a temporary file in WORK, you must use a two-level name, such as WORK.NAME.

The USER library enables you to read, create, and write to files in a SAS library other than WORK without specifying a libref as part of the SAS filename. Once you associate the libref USER with a SAS library, SAS stores any file with a one-level name in that library. Unlike the WORK library, files stored in this library are not deleted by SAS when the session terminates.

You can assign the USER libref using one of the following methods:

In this example, the LIBNAME statement is used with a DATA step, which stores the data set REGION in a permanent SAS library.

libname user 'SAS-library';
data region;
… more DATA step statements …
run;

In this example, the LIBNAME function assigns the USER libref:

data _null_;
   x=libname ('user', 'SAS-library');
run;

When assigning a libref using the USER= system option, you must first assign a libref to a SAS library, and then use the USER= system option to specify that library as the default for one-level names. In this example, the DATA step stores the data set PROCHLOR in the SAS library TESTLIB.

libname testlib 'SAS-library';
options user=testlib;
data prochlor;
… more DATA step statements …
run;

The USER libref overrides the default libref WORK for one-level names. When you refer to a file by a one-level name, SAS looks first for the libref USER. If USER is assigned to a SAS library, files with one-level names are stored there. If you have not assigned the libref USER to a library, the files with one-level names are stored in the temporary library WORK. To refer to SAS files in the WORK library while the USER libref is assigned, you must specify a two-level name with WORK as the libref. Data files that SAS creates internally still go to the WORK library.