In ABAQUS/CAE there are two types of commands: kernel commands and GUI commands.
Kernel commands
Kernel commands are used to build, analyze, and postprocess finite element models. Kernel commands are documented in the ABAQUS Scripting Reference Manual.
GUI commands
GUI commands are used by the user interface to process input gathered from the user and to construct a kernel command string that is sent to the kernel for execution. GUI commands are documented in the ABAQUS GUI Toolkit Reference Manual.