796

What is a portable way (e.g. for Linux and Windows) to get the current user's username? Something similar to os.getuid() would be nice:

>>> os.getuid()
42

# Does not currently exist in Python
>>> os.getusername()
'slartibartfast'

The pwd module works for Unix only. Some people suggest that getting the username under Windows can be complicated in certain circumstances (e.g., running as a Windows service).

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2
  • 6
    import pwd, os; print pwd.getpwuid(os.getuid()).pw_gecos or import pwd, os; print pwd.getpwuid(os.getuid()).pw_name Commented Mar 1, 2015 at 16:46
  • 2
    "username" is not even a portable concept. Consider microPython -- if you're running directly on hardware there's no such thing. Commented Aug 1, 2020 at 23:52

15 Answers 15

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1121

Look at getpass module

import getpass
getpass.getuser()
'kostya'

Availability: Unix, Windows

p.s. Per comment below "this function looks at the values of various environment variables to determine the user name. Therefore, this function should not be relied on for access control purposes (or possibly any other purpose, since it allows any user to impersonate any other)."

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16 Comments

There is nothing wrong with getpass.getuser(), since does not claim to authenticate the user. The purpose of the function is to determine who the user is claiming to be without asking the user directly.
That does not work if you've done a su. $ echo $USER hithwen $ su julia Password: $ echo $USER julia $ python >>> import getpass >>> getpass.getuser() 'hithwen'
@GregHewgill raises a very good point, but indeed, finding out the username in a simple unauthenticated way like this does have some applications. My current use-case: tagging some shared testing resources with a username for easy cleanup later. (So it's easier to figure out whose mess is whose.)
And I agree with @GregHewgill for the access control purposes, but completely disagree with 'any other purpose' - that's like saying "Don't use $USER in a shell script". Great point about access control but there are plenty of other uses that don't involve auth.
@hithwen That's working as intended. It depends on which arguments you give to su. Perhaps you wanted to use su - julia.
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178

Combine os.getuid() with pwd.getpwuid():

import os
import pwd

def get_username():
    return pwd.getpwuid(os.getuid())[0]

See pwd docs for more details.

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7 Comments

Alternatively (slightly nicer to read): pwd.getpwuid(os.getuid()).pw_name.
What does it do on Windows? Perhaps one could try this, and if it fails, fall back to the crappy 'getpass/env var' methods.
@JonathanHartley: ImportError: No module named pwd
This method is on unix-like systems much superior to Konstantin Tenzin's answer, because it handles the sudo case correctly. (I am aware the OP didn';t ask for unix-like ssytems.)
Wrong answer -- this is NOT portable to Windows.
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140

You can also use:

os.getlogin()
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9 Comments

On linux, getlogin() returns the name of the "user logged in on the controlling terminal of the process." It therefore fails when there is no controlling terminal, e.g., in a mod_python application.
If you used su, then this won't return the current user, but the originally logged in user.
does work on windows...Python 3.4.1 (v3.4.1:c0e311e010fc, May 18 2014, 10:38:22) [MSC v.1600 32 bit (Intel)] on win32 Type "help", "copyright", "credits" or "license" for more information. >>> import os; os.getlogin() 'jrb'
It's only available on Windows for Python 3.x.
Thanks for this. The login user is not exactly what the poster asked for but it is what I was looking for.
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117

Windows:

os.environ.get('USERNAME')

Linux:

os.environ.get('USER')

Both:

os.environ.get('USER', os.environ.get('USERNAME'))

Note that environment variables can be modified by the user, so this is a potential security vulnerability. With this method, an attacker can easily fake their username.

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9 Comments

os.getenv(...) is deprecated in favour of os.environ[...].
Shouldn't it be USER instead of USERNAME?
@MikeGraham os.getenv doesn't seem to be deprecated..?
Yes, exactly USER vs USERNAME is exactly what is not portable, so it doesn't provide the correct answer.
USERNAME is for Windows, USER is for Linux
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26

These might work. I don't know how they behave when running as a service. They aren't portable, but that's what os.name and ifstatements are for.

win32api.GetUserName()

win32api.GetUserNameEx(...)

See: http://timgolden.me.uk/python/win32_how_do_i/get-the-owner-of-a-file.html

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3 Comments

This answer is at least as useful as the (useless) 25-vote upvoted unix-only answer.
>"At least as useful" Agreed. Presumably the right answer is a combination of the two.
If you're stuck on python 2 on Windows, this is the only safe way to do it. All the other ways can be tricked by running SET USERNAME=FAKE before your python command
26

If you are needing this to get user's home dir, below could be considered as portable (win32 and linux at least), part of a standard library.

>>> os.path.expanduser('~')
'C:\\Documents and Settings\\johnsmith'

Also you could parse such string to get only last path component (ie. user name).

See: os.path.expanduser

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2 Comments

Someone's home directory does not always reflect their username.
Unfortunately, if you set the HOME variable in Windows, this will return it that value.
20

psutil provides a portable way that doesn't use environment variables like the getpass solution. It is less prone to security issues, and should probably be the accepted answer as of today.

import psutil

def get_username():
    return psutil.Process().username()

Under the hood, this combines the getpwuid based method for unix and the GetTokenInformation method for Windows.

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2 Comments

Is there a function in there to get it without the domain or do I split it on the / ?
split on the "\\" if present, yes, see: github.com/giampaolo/psutil/issues/1049
17

To me using os module looks the best for portability: Works best on both Linux and Windows.

import os

# Gives user's home directory
userhome = os.path.expanduser('~')          

print "User's home Dir: " + userhome

# Gives username by splitting path based on OS
print "username: " + os.path.split(userhome)[-1]

Output:

Windows:

User's home Dir: C:\Users\myuser

username: myuser

Linux:

User's home Dir: /root

username: root

No need of installing any modules or extensions.

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2 Comments

This solution is clever, but makes some assumptions that aren't always true. There is no constraint that requires the username to appear in the homedir path on Linux. It just happens to be the case most of the time, but a sysadmin can set a user's homedir to whatever they want.
Setting the HOME variable defeats this.
16

Combined pwd and getpass approach, based on other answers:

try:
  import pwd
except ImportError:
  import getpass
  pwd = None

def current_user():
  if pwd:
    return pwd.getpwuid(os.geteuid()).pw_name
  else:
    return getpass.getuser()
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2 Comments

getpass.getuser() Retrieves non-empty string from these environment variables LOGNAME, USER, LNAME and USERNAME, in order. If none are set, then login name from password database is returned on systems which support pwd module, else raises exception. pw_name is also login name
I might only use the pwd side, but this is the only answer here that gets the name of the effective user ID.
9

None of the above worked in my case (scroll down to the actual solution).
The problem I'm getting with all solutions is the wrong username when running commands with sudo:

  • psutil soulution:
$ python3
>>> import psutil
>>> psutil.Process().username()
'ubuntu' # OK!

$ sudo su
$ python3
>>> import psutil
>>> psutil.Process().username()
'root' # OK!

$ sudo python3
>>> import psutil
>>> psutil.Process().username()
'root' # WRONG, should be ubuntu!
  • getpass solution:
$ python3
>>> import getpass
>>> getpass.getuser()
'ubuntu' # OK!

$ sudo su
$ python3
>>> import getpass
>>> getpass.getuser()
'root' # OK!

$ sudo python3
>>> import getpass
>>> getpass.getuser()
'root' # WRONG, should be ubuntu!
  • pwd + os.getuid solution:
$ python3
>>> import os, pwd
>>> pwd.getpwuid( os.getuid() )[ 0 ]
'ubuntu' # OK!

$ sudo su
$ python3
>>> import os, pwd
>>> pwd.getpwuid( os.getuid() )[ 0 ]
'root' # OK!

$ sudo python3
>>> import getpass
>>> getpass.getuser()
'root' # WRONG, should be ubuntu!
  • os.getlogin works a bit different, but still wrong:
$ python3
>>> import os
>>> os.getlogin()
'ubuntu' # OK!

$ sudo su
$ python3
>>> import os
>>> os.getlogin()
'ubuntu' # WRONG, should be root!


$ sudo python3
>>> import os
>>> os.getlogin()
'ubuntu' # OK!
  • os.getenv gives the same results:
$ python3
>>> import os
>>> os.getenv('SUDO_USER', os.getenv('USER'))
'ubuntu' # OK!

$ sudo su
$ python3
>>> import os
>>> os.getenv('SUDO_USER', os.getenv('USER'))
'ubuntu' # WRONG, should be root!


$ sudo python3
>>> import os
>>> os.getenv('SUDO_USER', os.getenv('USER'))
'ubuntu' # OK!

Switching SUDO_USER and USER gives the wrong result in sudo python3 case.

Actual solution (non-portable)

Solution is a bit tricky and rely on the default root home directory location but works for all cases:

$ python3
>>> import os
>>> 'root' if os.path.expanduser('~') == '/root' else os.getenv('SUDO_USER', os.getenv('USER'))
'ubuntu' # OK!

$ sudo su
$ python3
>>> import os
>>> 'root' if os.path.expanduser('~') == '/root' else os.getenv('SUDO_USER', os.getenv('USER'))
'root' #  OK!

$ sudo python3
>>> import os
>>> 'root' if os.path.expanduser('~') == '/root' else os.getenv('SUDO_USER', os.getenv('USER'))
'ubuntu' # OK!
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4 Comments

This is the answer to a very different question
But grateful for it - deals with the sudo issue for that very different question for those looking for the answer to it from a Google search that leads here. Perhaps only a somewhat different question.
sudo escalates so root is effectively the user. if you want to be able to define your own user, I recommend creating a -u/--user flag so you can do something like sudo ./foo.py -u myUser, etc
As the others said, the result you are getting is not wrong. The command is running as root for all intents and purposes. This may be useful to someone but it's not an answer to OP's question.
9

Using only standard python libs:

from os import environ
from sys import platform

def getUser():
    return environ["USERNAME"] if platform.startswith("win") else environ["USER"]

user = getUser()

Works on Windows, Mac or Linux.

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6 Comments

getpass is also a standard lib
doesnt work for me in win10, python3.7.4. its complaining about 'USER' not being found in envirnment variables I guess. I guess getpass is a better choice anyway.
The only thing that would cause this is if you run it from a drive other than C:. That is the only reason it would use the USER key and not USERNAME. This is literally just an if/else... All it does is use USERNAME if there is a C: drive else USER
This is just a hacky solution and will break if your current working directory is on another drive. Your answer doesn't really provide a benefit over the others. There are better ways to check the platform even if you wanted to go that way, but usually it's preferable to use something that's portable from the start.
@Rob Grant good edit
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8

For UNIX, at least, this works...

import commands
username = commands.getoutput("echo $(whoami)")
print username

edit: I just looked it up and this works on Windows and UNIX:

import commands
username = commands.getoutput("whoami")

On UNIX it returns your username, but on Windows, it returns your user's group, slash, your username.

--

I.E.

UNIX returns: "username"

Windows returns: "domain/username"

--

It's interesting, but probably not ideal unless you are doing something in the terminal anyway... in which case you would probably be using os.system to begin with. For example, a while ago I needed to add my user to a group, so I did (this is in Linux, mind you)

import os
os.system("sudo usermod -aG \"group_name\" $(whoami)")
print "You have been added to \"group_name\"! Please log out for this to take effect"

I feel like that is easier to read and you don't have to import pwd or getpass.

I also feel like having "domain/user" could be helpful in certain applications in Windows.

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4 Comments

WIndows returns domain/user not group/user
The commands module does not work on Windows. It's a UNIX specific module (see docs.python.org/2/library/commands.html). It's now deprecated and subprocess is recommended instead. user = subprocess.check_output("whoami").replace("\r\n", "")
2 remarks. commands.whoami did great, even in the context of a service running under a different username. i.e. with chpst -u nobody python ./manage.py celerycam --pidfile=/var/run/celerycam/celerycam.pid I got nobody. second, user = subprocess.check_output("whoami").strip() is more portable than the replace linefeeds above. commands vs subprocess seems nitpicky but commands is missing from python 3.
-1 for using unsafe methods, at the very least you should be using subprocess, but spawning a separate process for this is excessive regardless.
3

I wrote the plx module some time ago to get the user name in a portable way on Unix and Windows (among other things): http://www.decalage.info/en/python/plx

Usage:

import plx

username = plx.get_username()

(it requires win32 extensions on Windows)

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Comments

3

You can get the current username on Windows by going through the Windows API, although it's a bit cumbersome to invoke via the ctypes FFI (GetCurrentProcess → OpenProcessToken → GetTokenInformation → LookupAccountSid).

I wrote a small module that can do this straight from Python, getuser.py. Usage:

import getuser
print(getuser.lookup_username())

It works on both Windows and *nix (the latter uses the pwd module as described in the other answers).

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Comments

-4

this works for me:

import os
os.cmd("whoami")
print (os.cmd("whoami"))
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4 Comments

There is no os.cmd. Is this Python's built-in os module?
yes the built-in os module. running Python 3.7 running on a Pi4B with RaspberryOS Buster.
Hmm, interesting, because it's not listed in the Python 3.7 docs for the os module.
hhmmm a non-documented feature. normally called a "bug" :-)

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