Python en:Installation

If you have Python 2.x installed already, you do not have to remove it to install Python 3.0. You can have both installed at the same time.

For Linux and BSD users

If you are using a Linux distribution such as Ubuntu, Fedora, OpenSUSE or {put your choice here}, or a BSD system such as FreeBSD, then it is most likely you already have Python installed on your system.

To test if you have Python already installed on your Linux box, open a shell program (like konsole or gnome-terminal) and enter the command python -V as shown below.

   $ python -V
   Python 3.0b1

Note

$ is the prompt of the shell. It will be different for you depending on the settings of your OS, hence I will indicate the prompt by just the $ symbol.

If you see some version information like the one shown above, then you have Python installed already.

However, if you get a message like this one:

   $ python -V
   bash: Python: command not found

Then you don't have Python installed. This is highly unlikely but possible.

Note

If you have Python 2.x already installed, then try python3 -V.

In this case, you have two ways of installing Python on your system.

• You can compile Python from the source code and install it. The compilation instructions are provided at the website.
• [This option will be available after the final release of Python 3.0] Install the binary packages using the package management software that comes with your OS, such as apt-get in Ubuntu/Debian and other Debian-based Linux, yum in Fedora Linux, pkg_add in FreeBSD, etc. Note that you will need an internet connection to use this method. Alternatively, you can download the binaries from somewhere else and then copy to your PC and install it.

For Windows Users

Visit http://www.python.org/download/releases/3.0/ and download the latest version from this website, which was 3.0 beta 1 as of this writing. This is just 12.8 MB which is very compact compared to most other languages or software. The installation is just like any other Windows-based software.

Caution

When you are given the option of unchecking any "optional" components, don't uncheck any! Some of these components can be useful for you, especially IDLE.

An interesting fact is that majority of Python downloads are by Windows users. Of course, this doesn't give the complete picture since almost all Linux users will have Python installed already on their systems by default.

DOS Prompt

If you want to be able to use Python from the Windows command line i.e. the DOS prompt, then you need to set the PATH variable appropriately.

For Windows 2000, XP, 2003 , click on Control Panel -> System -> Advanced -> Environment Variables. Click on the variable named PATH in the 'System Variables' section, then select Edit and add ;C:\Python30 to the end of what is already there. Of course, use the appropriate directory name.

For older versions of Windows, add the following line to the file C:\AUTOEXEC.BAT : 'PATH=%PATH%;C:\Python30' (without the quotes) and restart the system. For Windows NT, use the AUTOEXEC.NT file.

For Mac OS X Users

Mac OS X Users will find Python already installed on their system. Open the Terminal.app and run python -V and follow the advice in the above Linux section.

Summary

For a Linux system, you most probably already have Python installed on your system. Otherwise, you can install it using the package management software that comes with your distribution. For a Windows system, installing Python is as easy as downloading the installer and double-clicking on it. From now on, we will assume that you have Python installed on your system.

Next, we will write our first Python program.