How can I find the current OS in Python?

If you want user readable data but still detailed, you can use platform.platform()

>>> import platform
>>> platform.platform()
'Linux-3.3.0-8.fc16.x86_64-x86_64-with-fedora-16-Verne'

platform also has some other useful methods:

>>> platform.system()
'Windows'
>>> platform.release()
'XP'
>>> platform.version()
'5.1.2600'

Here's a few different possible calls you can make to identify where you are, linux_distribution and dist seem to have gone from recent python versions, so they have a wrapper function here.

import platform
import sys

def linux_distribution():
  try:
    return platform.linux_distribution()
  except:
    return "N/A"

def dist():
  try:
    return platform.dist()
  except:
    return "N/A"

print("""Python version: %s
dist: %s
linux_distribution: %s
system: %s
machine: %s
platform: %s
uname: %s
version: %s
mac_ver: %s
""" % (
sys.version.split('\n'),
str(dist()),
linux_distribution(),
platform.system(),
platform.machine(),
platform.platform(),
platform.uname(),
platform.version(),
platform.mac_ver(),
))

The outputs of this script ran on a few different systems (Linux, Windows, Solaris, MacOS) and architectures (x86, x64, Itanium, power pc, sparc) is available here: https://github.com/hpcugent/easybuild/wiki/OS_flavor_name_version

e.g. Solaris on sparc gave:

Python version: ['2.6.4 (r264:75706, Aug  4 2010, 16:53:32) [C]']
dist: ('', '', '')
linux_distribution: ('', '', '')
system: SunOS
machine: sun4u
platform: SunOS-5.9-sun4u-sparc-32bit-ELF
uname: ('SunOS', 'xxx', '5.9', 'Generic_122300-60', 'sun4u', 'sparc')
version: Generic_122300-60
mac_ver: ('', ('', '', ''), '')

or MacOS on M1

Python version: ['2.7.16 (default, Dec 21 2020, 23:00:36) ', '[GCC Apple LLVM 12.0.0 (clang-1200.0.30.4) [+internal-os, ptrauth-isa=sign+stri'] 
dist: ('', '', '') 
linux_distribution: ('', '', '') 
system: Darwin 
machine: arm64 
platform: Darwin-20.3.0-arm64-arm-64bit 
uname: ('Darwin', 'Nautilus.local', '20.3.0', 'Darwin Kernel Version 20.3.0: Thu Jan 21 00:06:51 PST 2021; root:xnu-7195.81.3~1/RELEASE_ARM64_T8101', 'arm64', 'arm') 
version: Darwin Kernel Version 20.3.0: Thu Jan 21 00:06:51 PST 2021; root:xnu-7195.81.3~1/RELEASE_ARM64_T8101 
mac_ver: ('10.16', ('', '', ''), 'arm64')

import os
print(os.name)

This gives you the essential information you will usually need. To distinguish between, say, different editions of Windows, you will have to use a platform-specific method.

I usually use sys.platform to get the platform. sys.platform will distinguish between linux, other unixes, and OS X, while os.name is "posix" for all of them.

For much more detailed information, use the platform module. This has cross-platform functions that will give you information on the machine architecture, OS and OS version, version of Python, etc. Also it has os-specific functions to get things like the particular linux distribution.