typing python -vand if that does not work try python -vand failing that try python - if any of these work you now know that you already have python installedwhat version it isand what it is called (in this book we use the name python but use whatever name worked for youfor examplepython if you don' have any version of python installedread on for windows and mac os xeasy-to-use graphical installer packages are provided that take you step-by-step through the installation process these are available from www python org/download for windowsdownload the "windows msi installer"unless you know for sure that your machine has different processor for which separate installer is supplied--for exampleif you have an amd get the "windows amd msi installeronce you've got the installerjust run it and follow the on-screen instructions for linuxbsdand other unixes (apart from mac os for which dmg installation file is provided)the easiest way to install python is to use your operating system' package management system in most cases python is provided in several separate packages for examplein ubuntu (from version )there is python for pythonidle-python for idle ( simple development environment)and python -doc for the documentation--as well as many other packages that provide add-ons for even more functionality than that provided by the standard library (naturallythe package names will start with python for the python versionsand so on if no python packages are available for your operating system you will need to download the source from www python org/download and build python from scratch get either of the source tarballs and unpack it using tar xvfz python- tgz if you got the gzipped tarball or tar xvfj python- tar bz if you got the bzip tarball (the version numbers may be differentfor examplepythontgz or pythontar bz in which case simply replace with your actual version number throughout the configuration and building are standard firstchange into the newly created python- directory and run /configure (you can use the --prefix option if you want to do local install nextrun make it is possible that you may get some messages at the end saying that not all modules could be built this normally means that you don' have some of the required libraries or headers on your machine for exampleif the readline module could not be builtuse the package management system to install the corresponding development libraryfor examplereadline-devel on fedorabased systems and readline-dev on debian-based systems such as ubuntu another module that may not build straight away is the tkinter module--this depends on both the tcl and tk development librariestcl-devel and tk-devel on fedora-based systemsand tcl -dev and tk -dev on debian-based systems (and where the minor version may not be unfortunatelythe relevant package names are not always so obviousso you might need to ask for help on