IBM System 360 User Manual page 13

When you use a command to request work, the command establishe~ the
scope of the work to the system. For some commands, the scope of the
work encompasses several operations that you can identify separately.
After entering the command, you may specify one of the separately
identifiable operations by entering a subcommand. A subcommand. like a
command, is a request for work; however, the work requested by a
sUbcommand is a particular operation within the scope of work
established by a command.
The commands and subcommands recognized by TSO form the TSO command
language. The command language~is designed to be easy to use. The
command names and subcommand names are typically familiar English words,
often verbs, that describe the work to be done. The number of command
names and subcommand names that you must learn has been kept to a
minimum. (Your installation can add its own commands to perform
functions not provided by the TSO command language.)
Besides entering the name of the command or subcommand, you are often
required to specify additional information to pinpoint the function you
want performed. You define the additional information with operands
(words or numbers that accompany the command names and subcommand
names). Most of the operands have default values that are used by the
system if you choose to omit the operand from the command or subcommand.
However, some operands do not have default values. If you fail to
provide a required operand for which there is no default, the system
sends you a prompting message asking you to supply the operands. The
publication, Command Language Reference shows all operands for each
command, indicates the default values where applicable, and describes
how to enter the commands.
You can abbreviate many of the command names, subcommand names and
operands. Together, the defaults and abbreviations decrease the amount
of typing required. (The abbreviations and their use are discussed in
the publication, Command Language Reference.)
Figure 1 lists the commands and their subcommands in alphabetical
order.
Wha t you Must Know to Use TSO 13