pythonstartup it contains the path of an initialisation file containing python source code it is executed every timeyou start the interpreter it is named as pythonrc py in unix and it contains commands that load utilities or modify pythonpath pythoncaseok it is used in windows to instruct pythonto find the first case-insensitive match in an import statement set this variable to any value to activate it pythonhome it is an alternative module search path it is usually embedded in the pythonstartup or pythonpath directories to make switching module libraries easy running python there are three different ways to start pythonwhich are as followsinteractive interpreter you can start python from unixdosor any other systemthat provides you command line interpreter or shell window enter python the command line start coding right away in the interactive interpreter $python unix/linux or pythonunix/linux or :python windows/dos hereis the list of all the available command line optionswhich is as mentioned belowsr no option description - it provides debug output - it generates optimised bytecode (resulting in pyo files