System symbols represent the values in shared commands that are unique on different systems. Each system defines its own values to system symbols, and replaces the system symbols with those values when processing shared commands.
To use system symbols in system commands, first see the topic that describes system symbols in z/OS MVS Initialization and Tuning Reference to understand the types of system symbols, the elements that comprise them, and the general rules for using them. Second, see the topic on sharing system commands in z/OS MVS Planning: Operations for information about planning to share commands. Then read the rest of this topic.