Syntax rules for VTAM operator commands

The first two parts of each command, the command name and the first operand cannot be changed by the USS table.

Command	1st Operand
DISPLAY	NET
MODIFY	procname
VARY	NET

All other operands of a VTAM® command can be changed in a user-defined table.

Note: The VTAM START and HALT commands cannot be changed through a USS table.

Include definitions for all operands, even if you are not redefining all of them. Any operand that does not appear in the user table will be passed unconverted to the command processor.

Operands that describe the command function (such as TERM on the VARY NET,TERM command, ADJSSCPS on the DISPLAY NET,ADJSSCPS) cannot be changed. However, other operands can be redefined (such as LU1, LU2, and NOTIFY on the VARY NET,TERM command).
```
VARY NET,TERM,LU1=luname,LU2=lu2name,NOTIFY=YES
```
Keyword operands can be converted into another operand with the same value. For example
```
MODIFY MSG=YES
```
can be converted into
```
MODIFY MSGMOD=YES
```
It is also possible to specify a default value to be used if the operand is omitted or specified without a value.
```
USSPARM PARM=MSGMOD,VALUE=YES
USSPARM PARM=MSGMOD,DEFAULT=YES
```
```
MODIFY procname,MSGMOD=,
MODIFY procname
```
An operand value specified by the operator cannot be replaced using the USS table.
For example,
```
MODIFY procname,MSGMOD=NO
```
cannot be converted into
```
MODIFY procname,MSGMOD=YES
```
Commands cannot be redefined to perform more than one function. For example, the following commands
```
DISPLAY NET,CDRMS
DISPLAY NET,CLSTRS
```
cannot be converted to one command
```
DISPLAY NET,CDRMS,CLSTRS
```