you can start an interactive session on windows and earlier by clicking your start buttonpicking the all programs optionclicking the python entryand selecting the "python (command line)menu option you can also achieve the same effect on windows and other platforms by typing python as system command line in your system' console window ( command prompt window on windowsanother alternative is to launch idleas its main python shell window is an interactive session depending on your platform and pythonif you have not set your system' path variable to find pythonyou may need to cd to where python is installedor type its full directory path instead of just python ( :\python \python on windowsunless you're using the launcher you type system command lines in whatever your platform provides as system consolea command prompt window on windowsan xterm or terminal window on unixlinuxand mac os xand so on you type this at the system' promptnot at the python interactive interpreter' "prompt--be careful not to confuse these prompts code in script (reallymodulefile can be run with system command linesfile icon clicksimports and reloadsthe exec built-in functionand ide gui selections such as idle' run-run module menu option on unixthey can also be run as executables with the #trickand some platforms support more specialized launching techniques ( drag and dropin additionsome text editors have unique ways to run python codesome python programs are provided as standalone "frozen binaryexecutablesand some systems use python code in embedded modewhere it is run automatically by an enclosing program written in language like cc++or java the latter technique is usually done to provide user customization layer scripts that print and then exit cause the output file to disappear immediatelybefore you can view the output (which is why the input trick comes in handy)error messages generated by your script also appear in an output window that closes before you can examine its contents (which is one reason that system command lines and ides such as idle are better for most development python imports (loadsa module only once per processby defaultso if you've changed its source code and want to run the new version without stopping and restarting pythonyou'll have to reload it you must import module at least once before you can reload it running files of code from system shell command linevia an icon clickor via an ide such as idle generally makes this nonissueas those launch schemes usually run the current version of the source code file each time within the text edit window of the file you wish to runselect the window' run-run module menu option this runs the window' source code as top-level script file and displays its output back in the interactive python shell window how you run programs