The output of SHOW commands can be sent to the system files SYSOUT and/or SYSLST and, in the case of commands which support this, also in S variables.
SYSOUT and SYSLST output consists of constant labels and items of variable information. In order for current parts of the full set of information to be further processed in procedures, the output must be redirected to a file. Then the individual items can be selected by string processing. This calls for precise understanding of the output layout. As SYSOUT and SYSLST output is subject to change from version to version, user-defined procedures need to be continually updated to match.
With structured output in S variables, each item of information can be stored as the contents of an S variable. The names of the S variables allow the user to access the required individual item of information in the SHOW command, regardless of the output layout. The names of the S variables are preset for each SHOW command and are guaranteed for subsequent versions; in other words, they are not subject to change.