I recently upgraded to 18.10 from 18.04, but I am facing a new problem.

When I type python, I am getting this

Python 3.7.3 (default, Apr 9 2019, 04:56:51)

[GCC 8.3.0] on linux

But when I type python3, I am getting an error

bash: /usr/lib/command-not-found: /usr/bin/python3: bad interpreter: No such file or directory

I couldnt opem ny terminal so I changed the very first line of /usr/bin/gnome-terminal to:

!#usr/bin/python from #!usr/bin/python3 since then I am able to open my terminal. Upon entering sudo apt-get update I am getting this error

sh: 1: /usr/lib/cnf-update-db: not found
Reading package lists... Done
E: Problem executing scripts APT::Update::Post-Invoke-Success 'if /usr/bin/test -w /var/lib/command-not-found/ -a -e /usr/lib/cnf-update-db; then /usr/lib/cnf-update-db > /dev/null; fi'
E: Sub-process returned an error code

No matter whether I enter




I am getting this error bash: /usr/local/bin/pip: /usr/bin/python3: bad interpreter: No such file or directory I tried sudo update-alternatives --config python3 I got There is only one alternative in link group python3 (providing /usr/bin/python3.6): /usr/bin/python3.7 Nothing to configure.

But when I type sudo update-alternatives --config python I am getting

There are 2 choices for the alternative python (providing /usr/bin/python).

Selection Path Priority Status ------------------------------------------------------------

0 /usr/bin/python3.6 2 auto mode

* 1 /usr/bin/python3.6 2 manual mode

2 /usr/bin/python3.7 2 manual mode

The Software&Updates and Software Updater are also not loading when I click on their icon

  • 1
    Can you explain what changes you made (or attempted to make, but failed) to the system-provided Python and Python3? And what you were trying to accomplish with those changes? – user535733 May 22 at 18:17
  • I was trying to upgrade to 19.04 but I got an error something like "Your python3 install is corrupted. Please fix the '/usr/bin/python3' symlink. – learner May 22 at 18:19
  • So I entered the following command(copy-pasted from the community) sudo rm /usr/bin/python3 then sudo ln -sf /usr/bin/python3.6 /usr/bin/python3 then sudo update-alternatives --install /usr/bin/python3.6 python3 /usr/bin/python3 2 and finally sudo update-alternatives --config python3 – learner May 22 at 18:21
  • I followed this answer askubuntu.com/questions/1144048/… – learner May 22 at 18:21
  • I ran sudo apt install --reinstall python3-minimal everything went back to normal, but still not able to upgrade to 19.04 , when I ran "sudo do-release-upgrade' I still get "Your python3 install is corrupted. Please fix the '/usr/bin/python3' symlink. " – learner May 22 at 18:31

python from your command line must point to python2.7

You might have messed up your apt/aptitude

Delete your symlink and replace with the default python

sudo rm /usr/bin/python


sudo ln -sf /usr/bin/python2.7 /usr/bin/python

Similarly for Ubuntu 18.10 python3 points to python3.6

sudo rm /usr/bin/python3


sudo ln -sf /usr/bin/python3.6 /usr/bin/python3

Hope this helps

  • Now can I upgrade to 19.04 – learner May 22 at 18:55
  • Try doing that and after upgrade just make sure python and python3 points to the correct symlinks. – z3phyr May 22 at 19:00
  • was it working?@learner – z3phyr Jun 10 at 16:20
  • yes it worked, thanks for the help :) – learner Jun 11 at 4:18

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