Intrinsics are run-to-completion commands that typically do not process signal data. In contrast to primitives and macros, which loop over sections of data until an end-of-file condition occurs, the primary processing section of an intrinsic executes only once. Commands that perform control functions or scalar calculations are generally implemented as intrinsics.
An intrinsic runs in the thread of the shell that dispatches it. An intrinsic cannot be executed until it has been added to the dictionary of the option tree in which it is packaged. Although intrinsics tend to be "system oriented" commands, there is no requirement that intrinsics be contained only in the sys option tree.