nonstandard directories (see python org' download page for more detailspy_pythonpy_python py_python these settings are used to specify default pythons when you are using the new (at this writingwindows launcher that ships with python and is available separately for other versions since we'll be exploring the launcher in appendix bi'll postpone further details here note that because these environment settings are external to python itselfwhen you set them is usually irrelevantthis can be done before or after python is installedas long as they are set the way you require before python is actually run--be sure to restart your python ides and interactive sessions after making such changes if you want them to apply tkinter and idle guis on linux and macs the idle interface described in is python tkinter gui program the tkinter module (named tkinter in xis gui toolkit that is automatically installed with standard python on windowsand is an inherent part of mac os and most linux installations on some linux systemsthoughthe underlying gui library may not be standard installed component to add gui support to your python on linux if neededtry running command line of the form yum tkinter to automatically install tkinter' underlying libraries this should work on linux distributions (and some other systemson which the yum installation program is availablefor otherssee your platform' installation documentation as also discussed in on mac os idle probably lives in the macpython (or python mfolder of your applications folder (along with pythonlauncherused for starting programs with clicks in finder)but be sure to see the download page at python org if idle has problemsyou may need to install an update on some os versions (see how to set configuration options the way to set python-related environment variablesand what to set them todepends on the type of computer you're working on and againremember that you won' necessarily have to set these at all right awayespecially if you're working in idle (described in and save all your files in the same directoryconfiguration is probably not required up front but supposefor illustrationthat you have generally useful module files in directories called utilities and package somewhere on your machineand you want to be able to import these modules from files located in other directories that isto load file called configuring python