Using External Files and Devices

Using Environment Variables to Assign Filerefs in UNIX Environments

An environment variable can also be used as a fileref to refer to DISK files. The variable name must be in all uppercase characters, and the variable value must be the full pathname of the external file; that is, the filename must begin with a slash.

Note: If a variable and a fileref have the same name but refer to different files, SAS uses the fileref. For example, the %INCLUDE statement below refers to file /users/myid/this_one. [cautionend]

filename ABC '/users/myid/this_one';
x setenv ABC /users/myid/that_one;
%include ABC;

Reading a Data File

If you want to read the data file /users/myid/educ.dat, but you want to refer to it with the INED environment variable, you can define the variable at two times:

Before you invoke SAS. See Defining Environment Variables in UNIX Environments. For example, in the Korn shell, you use the following:
```
export INED=/users/myid/educ.dat
```
After you invoke SAS by using the X statement (see Executing Operating System Commands from Your SAS Session) and the SAS setenv command:
```
x setenv INED /users/myid/educ.dat;
```

After INED is associated with the file /users/myid/educ.dat, you can use ined as a fileref to refer to the file in the INFILE statement:

infile ined;

Writing to an External File

The same method applies if you want to write to an external file. For example, you can define OUTFILE before you invoke SAS:

OUTFILE=/users/myid/scores.dat
export OUTFILE

Then, use the environment variable name as a fileref to refer to the file:

file OUTFILE;

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