CALL SYSTEM

CALL SYSTEM

Issues operating environment commands

OS/2 specifics: command must be a valid OS/2 command

Syntax
Details
Comparison
Examples
	Example 1: Executing Operating System Commands Conditionally
	Example 2: Obtaining a Directory Listing
See Also

Syntax

CALL SYSTEM(command)

command

can be any of the following:

an operating environment command enclosed in quotes or the name of a OS/2 application that is enclosed in quotes
an expression whose value is an operating environment command or the name of a OS/2 application
the name of a character variable whose value is an operating environment command or the name of a OS/2 application.

Details

If you are running SAS interactively and the command that you run is an OS/2-based command or program, the command executes in a command prompt window. By default, you must type exit to return to your SAS session.

Comparison

The CALL SYSTEM routine is similar to the X command. However, the CALL SYSTEM routine is callable and can therefore be executed conditionally. An example of using the CALL SYSTEM routine is given in Executing Operating Environment Commands Conditionally.

The values of the XSYNC and XWAIT system options affect how the CALL SYSTEM routine works. For more information about these options, see XSYNC and XWAIT.

Examples

Example 1: Executing Operating System Commands Conditionally

If you want to execute operating environment commands conditionally, use the CALL SYSTEM routine:

options noxwait;
data _null_;
   input flag $ name $8.;
   if upcase(flag)='Y' then
      do;
         command='md c:\'||name;
         call system(command);
      end;
   cards;
Y mydir
Y junk2
N mydir2
Y xyz
;

This example uses the value of the variable FLAG to conditionally create directories. After the DATA step executes, three directories have been created: C:\MYDIR, C:\JUNK2, and C:\XYZ. The directory C:\MYDIR2 is not created because the value of FLAG for that observation is not Y.

The X command is a global SAS statement. Therefore, it is important to realize that you cannot conditionally execute the X command. For example, if you submit the following code, the X statement is executed:

data _null_;
   answer='n';
   if upcase(answer)='y' then
      do;
         x 'md c:\extra';
      end;
run;

In this case, the directory C:\EXTRA is created regardless of whether the value of ANSWER is equal to 'n' or 'y'.

Example 2: Obtaining a Directory Listing

The following is an example of using the CALL SYSTEM routine to obtain a directory listing:

data _null_;
   call system('dir /w');
run;

In this example, the /W option for the DIR command instructs OS/2 to print the directory in the wide format instead of a vertical list format.

See Also

CALL SYSTEM routine in SAS Language Reference: Dictionary
Command: X
System option: XSYNC
System option: XWAIT

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