from the one in which you are working for examplethe following system command linerun from :\otherassumes python is in your system path but runs file located elsewherec:\codecd :\other :\otherpython :\code\script py if your path doesn' include python' directoryyou're not using the windows launcher' py programand neither python nor your script file is in the directory you're working inuse full paths for bothd:\otherc:\python \python :\code\script py usage notescommand lines and files running program files from system command lines is fairly straightforward launch optionespecially if you are familiar with command lines in general from prior work it' also perhaps the most portable way to run python programs since nearly every computer has some notion of command line and directory structure for newcomersthoughhere are few pointers about common beginner traps that might help you avoid some frustrationbeware of automatic extensions on windows and idle if you use the notepad program to code program files on windowsbe careful to pick the type all files when it comes time to save your fileand give the file py suffix explicitly otherwisenotepad will save your file with txt extension ( as script py txt)making it difficult to use in some schemesit won' be importablefor example worsewindows hides file extensions by defaultso unless you have changed your view options you may not even notice that you've coded text file and not python file the file' icon may give this away--if it doesn' have snake of some sort on ityou may have trouble uncolored code in idle and files that open to edit instead of run when clicked are other symptoms of this problem microsoft word similarly adds doc extension by defaultmuch worseit adds formatting characters that are not legal python syntax as rule of thumbalways pick all files when saving under windowsor use more programmer-friendly text editor such as idle idle does not even add py suffix automatically-- feature some programmers tend to likebut some users do not use file extensions and directory paths at system promptsbut not for imports don' forget to type the full name of your file in system command lines-that isuse python script py rather than python script by contrastpython' import statementswhich we'll meet later in this omit both the py file suffix and the directory path ( import script this may seem trivialbut confusing these two is common mistake how you run programs