TSO command
A command typed at a TSO prompt or on an ISPF command line to ask the system to do something directly.
Also written TSO commands
TSO commands are the instructions you can type to work with the system without writing a job. They cover the everyday tasks: listing your datasets, allocating a new one, deleting one, copying data, sending a message to another user, or submitting JCL.
They can be typed at a bare TSO prompt, but more often you use them from inside ISPF by prefixing them with TSO on a command line. For example, entering a command to submit a dataset for execution without leaving the screen you are on.
REXX programs are largely made of these commands. A REXX exec runs a sequence of TSO commands, checks the results, and decides what to do next, which is how a great deal of routine mainframe automation is written.
Learning a handful of them early pays off quickly. Even inside a menu-driven environment, being able to type the command directly is usually faster than navigating to the panel that does the same thing.
Related terms
- TSOTime Sharing Option: the interactive login environment on z/OS, where you get a command prompt and a session of your own.
- ISPFThe full-screen, menu-driven workbench most people use to do their day-to-day work on z/OS.
- REXXA readable scripting language used across the mainframe for automation, tooling and quick one-off tasks.
- SubmitHanding JCL to the system to be run, which queues it as a job and gives it a job number.
- DatasetWhat a mainframe calls a file: a named collection of records with a defined structure, rather than a loose stream of bytes.