Because SCons is written in Python, you need to have Python installed on your system to use SCons. Before you try to install Python, you should check to see if Python is already available on your system by typing python -V (capital 'V') or python --version at your system's command-line prompt. For Linux/Unix/MacOS/BSD type systems this looks like:

$ python -V
Python 3.7.1
    

Note to Windows users: there are many different ways Python can get installed or invoked on Windows, it is beyond the scope of this guide to unravel all of them. Try using the Python launcher (see PEP 397) by using the name py instead of python, if that is not available drop back to trying python.

C:\>py -V
Python 3.7.1
    

If Python is not installed on your system, or is not findable in the current search path, you will see an error message stating something like "command not found" (on UNIX or Linux) or "'python' is not recognized as an internal or external command, operable progam or batch file" (on Windows cmd). In that case, you need to install Python (or fix the search path) before you can install SCons.

The canonical location for information about downloading and installing Python is http://www.python.org/download/. See that page and associated links to get started.

For Linux systems, Python is almost certainly available as a supported package, possibly installed by default; this is often preferred over installing by other means, and is easier than installing from source code. Many such systems have separate packages for Python 2 and Python 3 - make sure the Python 3 package is installed, as SCons requires it. Building from source may still be a useful option if you need a version that is not offered by the distribution you are using.

SCons will work with Python 3.5 or later. If you need to install Python and have a choice, we recommend using the most recent Python version available. Newer Pythons have significant improvements that help speed up the performance of SCons.