When used non-interactively, the Python interpreter monitors the command line and parses all input before the command is actually executed. The following snippet shows all the possible options available when calling Python from the command line:

python [-bBdEhiIOqsSuvVWx?] [-c command | -m module-name | script | - ] [args] 

When working with a command line interface (CLI), examples of shell commands often show square brackets [] to indicate optional instructions. In this case, there are three groups of optional input that can be provided to the python command: generic options, interface options, and arguments.