Using Python's os.path, how do I go up one directory?

To get the folder of a file just use:

os.path.dirname(path) 

To get a folder up just use os.path.dirname again

os.path.dirname(os.path.dirname(path))

You might want to check if __file__ is a symlink:

if os.path.islink(__file__): path = os.readlink (__file__)

If you are using Python 3.4 or newer, a convenient way to move up multiple directories is pathlib:

from pathlib import Path

full_path = "path/to/directory"
str(Path(full_path).parents[0])  # "path/to"
str(Path(full_path).parents[1])  # "path"
str(Path(full_path).parents[2])  # "."

python-3.9.0.exe /quiet InstallAllUsers=1 PrependPath=1 Include_test=0

python-3.9.0.exe InstallAllUsers=0 Include_launcher=0 Include_test=0
    SimpleInstall=1 SimpleInstallDescription="Just for me, no test suite."

<Options>
    <Option Name="InstallAllUsers" Value="no" />
    <Option Name="Include_launcher" Value="0" />
    <Option Name="Include_test" Value="no" />
    <Option Name="SimpleInstall" Value="yes" />
    <Option Name="SimpleInstallDescription">Just for me, no test suite</Option>
</Options>

python-3.9.0.exe /layout [optional target directory]

nuget.exe install python -ExcludeVersion -OutputDirectory .
nuget.exe install pythonx86 -ExcludeVersion -OutputDirectory .