Everything you need to know about the switch to Python 3
Table of Contents
- About the transition
- Keeping backwards compatibility in Kali
- Frequently Asked Questions
About the transition
Kali Linux fully switched to Python 3. This means that any tool packaged by
Kali that was using Python 2 has been either dropped or converted to use Python 3.
Any tool converted to Python 3 contains only scripts with
/usr/bin/python3 as their shebang.
Concerning the packages that come straight from Debian, they did the same
on most packages, but there are a few exceptions where packages are
allowed to continue to rely on Python 2. However those packages
have been updated so that all their scripts use
/usr/bin/python2 as their shebang and so that they depend on the
python2 binary package (instead of the former
Thanks to those changes, Debian no longer need to provide
/usr/bin/python and recent upgrades will effectively get rid of that
Unfortunately, when you download a Python script on the web, it will
/usr/bin/python as its shebang. If you try to execute it
without fixing the shebang line, you will end up with an error like
zsh: /home/kali/test.py: bad interpreter: /usr/bin/python: no such file or directory
In Debian, you can reinstate the
/usr/bin/python symlink by installing:
python-is-python2if you want to have it point to
python-is-python3if you want to have it point to
Keeping backwards compatibility in Kali
Given the large number of users that would not know how to avoid the above
error, we decided that Kali would continue to ship Python 2 by default (as
long as Debian still provides it) and that
/usr/bin/python would point
to it. We are also keeping a few common external modules (like
so that random exploit scripts have a reasonable chance to run
Howewer, pip for Python2 (aka python-pip) is gone,
/usr/bin/pip is the
/usr/bin/pip3 and it will install modules for Python 3. See the
FAQ below for more information.
This compatibility has been implemented by having
offsec-awae-python2 so that
they are installed by default while being removable by users that would
like to get rid of them.
To make users aware of this situation, we are displaying a promiment message on login:
┏━(Message from Kali developers) ┃ ┃ We have kept /usr/bin/python pointing to Python 2 for backwards ┃ compatibility. Learn how to change this and avoid this message: ┃ ⇒ https://www.kali.org/docs/general-use/python3-transition/ ┃ ┗━(Run “touch ~/.hushlogin” to hide this message)
The hope is that they will read this article and know how do deal with the various issues that they will encounter.
Frequently Asked Questions
I have downloaded a Python script, what should I do?
You need to inspect its shebang line. The shebang line is the first
line of a script and it starts with
#! followed by the path
of the interpreter that will be used to execute the script.
If the interpreter is
/usr/bin/python, you should read the documentation
to see whether the script can run with Python 3. If yes, then you should
update the shebang line to point to
/usr/bin/python3. Otherwise you
should update it to point to
Good shebang lines that can be kept:
Bad shebang lines that need to be updated:
How can I get rid of the login message?
The message will only be displayed as long as
/usr/bin/python points to
the deprecated Python 2. Now that you know about this situation and that
you know how to fix the shebang line of old scripts, you can safely get
[email protected]:~$ sudo apt remove python-is-python2
Or you can decide to make it point to Python 3:
[email protected]:~$ sudo apt install -y python-is-python3
Either of those actions will get rid of the login message.
Alternatively, if you want to keep
/usr/bin/python pointing to
python2 and you still want to disable the message, you can do
[email protected]:~$ mkdir -p ~/.local/share/kali-motd [email protected]:~$ touch ~/.local/share/kali-motd/disable-old-python-warning
I have a Python 2 script that doesn’t run, what should I do?
If your Python 2 script uses modules that are not among those that we ship
offsec-awae-python2 compatibility package (see list
then you can try
pyenv to setup a fully isolated Python 2 environment
where you can use pip to install supplementary modules. See our Using EoL
Python versions on Kali article.
I want pip for Python 2, how can I get it back?
pyenv. See our Using EoL Python versions on
I wrote a Python script, what should I do?
Be nice with end users:
- document clearly whether your code runs with Python 3 or Python 2
/usr/bin/python2as the shebang line, it’s more expressive than
/usr/bin/pythonand is more likely to have the desired result
- update it for Python 3 compatibility if that’s not the case yet
Updated on: 2022-Nov-30