Run scons on Windows 10 environment with Python 2.7 and Python 3

Question

How can I run scons on Windows 10 when Python 3.6.1 and Python 2.7.13 is installed? When typing python into my command window I get the following output:

Python 3.6.1 (v3.6.1:69c0db5, Mar 21 2017, 18:41:36) [MSC v.1900 64 bit (AMD64)] on win32
Type "help", "copyright", "credits" or "license" for more information.
>>>

Since I personally use Python 3.6.x this is fine for me and I do not want to change this.

When typing py -2 into my command window I get the following output:

Python 2.7.13 (v2.7.13:a06454b1afa1, Dec 17 2016, 20:42:59) [MSC v.1500 32 bit (Intel)] on win32
Type "help", "copyright", "credits" or "license" for more information.
>>>

scons does not work with Python 3.x. It needs to be executed with Python 2.7.x. How can I "tell" scons to use Python 2.7.x?

When I just type scons into the command prompt I get the following output:

PS C:\dev\projectX> scons
Fatal Python error: Py_Initialize: unable to load the file system codec
ModuleNotFoundError: No module named 'encodings'

Current thread 0x00007050 (most recent call first):

Answer 1

Try Changing line 23 in scons.bat from:

python "%scriptname%" %*

to

py -2  "%scriptname%" %*

Note that work on getting SCons to run under both py 2 and py 3.5+ is mostly done and should be released in the next month (or so)

Answer 2

Before running scons in Powershell, amend the PATH environment variable to put your Python 2.7 installation at the front. Something like:

SET PATH=C:\Python27;%path%