Using command tables to define commands

ISPF implements system, user, site and application commands through the use of command tables.

A system command table (ISPCMDS) is distributed with ISPF in the table input library. An application can provide an application command table by including a table named xxxxCMDS in its table input library, where xxxx is a 1- to 4-character application ID. You can also add up to 3 user command tables and up to 3 site command tables to the ISPF Configuration table. This is a permanent place for your set of user-defined commands. When IBM® updates the ISPF command table, you do not need to re-add your commands. By setting the Before or After option, you can search the site command tables either before or after the ISP command table. The default option is Before. If the application's table input library is defined with the LIBDEF service, the LIBDEF must be active when the SELECT service call that invokes the application is issued, and the PASSLIB parameter must be specified.

You can define an application command table using either:

The command table utility described in the Command Table Utility (Option 3.9) section of the z/OS V2R2 ISPF User's Guide Vol II.
The Dialog Tag Language (DTL) and ISPF conversion utility. See the z/OS V2R2 ISPF Dialog Tag Language Guide and Reference for the tags you must use.

When a user enters a command, the DM component searches the application command table (if any), then the user command tables (if any), then the site command tables (if any), and finally the system command table, ISPCMDS. This is the default search order, which assumes the option Before for the site command tables. If you choose the option After for these tables, they are searched after ISPCMDS. If it finds the command, action is taken immediately. If it does not find the command in the application or system tables, the command is passed to the dialog, unaltered, in the command field. The dialog must then take appropriate action.