>>> import os
>>> os.environ.keys()
['WINBOOTDIR', 'PATH', 'USER', 'PP2EHOME', 'CMDLINE', 'PYTHONPATH', 'BLASTER', 
'X', 'TEMP', 'COMSPEC', 'PROMPT', 'WINDIR', 'TMP']
>>> os.environ['TEMP']
'C:\\windows\\TEMP'
>>>
>>> os.environ['TEMP'] = r'c:\temp'
>>> os.environ['TEMP']
'c:\\temp'




C:\Part2\System\Environment>set USER=Bob

C:\Part2\System\Environment>python echoenv.py
echoenv... Hello, Bob

C:\Part2\System\Environment>python setenv.py
setenv... Bob
echoenv... Hello, Brian
echoenv... Hello, Arthur
?Guido
echoenv... Hello, Guido

C:\Part2\System\Environment>echo %USER%
Bob




>>> import os
>>> os.environ['USER'] = 'Mel'
>>> os.popen('python echoenv.py').read()
'echoenv... Hello, Mel\012'
>>>

C:\Part2\System\Environment>python
>>> import os
>>> os.environ['PYTHONPATH']
'C:\\PP2ndEd\\examples\\Part3;C:\\PP2ndEd\\examples\\Part2;C:\\PP2ndEd\\examples
\\Part2\\Gui;C:\\PP2ndEd\\examples\\Part1\\Preview\\Gui;C:\\PP2ndEd\\examples'
>>>
>>> import string
>>> for dir in string.split(os.environ['PYTHONPATH'], os.pathsep):
...   print dir
...
C:\PP2ndEd\examples\Part3
C:\PP2ndEd\examples\Part2
C:\PP2ndEd\examples\Part2\Gui
C:\PP2ndEd\examples\Part1\Preview\Gui
C:\PP2ndEd\examples