SQL*Loader is started when you specify the sqlldr command and, optionally, parameters that establish various characteristics of the load operation.
In situations where you always use the same parameters for which the values seldom change, it can be more efficient to specify parameters using the following methods, rather than on the command line:
Parameters can be grouped together in a parameter file. You could then specify the name of the parameter file on the command line using the PARFILE parameter.
Certain parameters can also be specified within the SQL*Loader control file by using the OPTIONS clause.
Parameters specified on the command line override any parameter values specified in a parameter file or OPTIONS clause.
SQL*Loader Command-Line Reference for descriptions of the SQL*Loader parameters
"PARFILE"