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I tried everything,I still have the error

sudo apt update

shows

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

I tried back and fort Pyhton2,3. Now

python --version
Python 2.7.18

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


ls -l /usr/bin/python*
lrwxrwxrwx 1 root root      18 Mar  2 09:37 /usr/bin/python -> /usr/bin/python2.7
lrwxrwxrwx 1 root root       9 Mar 13  2020 /usr/bin/python2 -> python2.7
-rwxr-xr-x 1 root root 3662032 Jul  1  2022 /usr/bin/python2.7
-rwxr-xr-x 1 root root 5494584 Nov 14 13:59 /usr/bin/python3.8
lrwxrwxrwx 1 root root      33 Nov 14 13:59 /usr/bin/python3.8-config -> x86_64-linux-gnu-python3.8-config
-rwxr-xr-x 1 root root 5762192 Dec  7 02:11 /usr/bin/python3.9
lrwxrwxrwx 1 root root      16 Mar 13  2020 /usr/bin/python3-config -> python3.8-config
-rwxr-xr-x 1 root root     384 Jan 25 09:33 /usr/bin/python3-futurize
-rwxr-xr-x 1 root root     388 Jan 25 09:33 /usr/bin/python3-pasteurize
-rwxr-xr-x 1 root root    5902 Jan 13  2020 /usr/bin/python3-wsdump
-rwxr-xr-x 1 root root    2555 Apr 14  2020 /usr/bin/python-argcomplete-check-easy-install-script3
-rwxr-xr-x 1 root root     314 Apr 14  2020 /usr/bin/python-argcomplete-tcsh3

This error when trying sudo relates to 2018 year. After

sudo update-alternatives --install /usr/bin/python3 python3 /usr/bin/python3.9 1

which python3

shows

/usr/bin/python3

which python3.9
/usr/bin/python3.9

One other consequence is that I can not open Terminal(Terminator) form Gnome.

how to fix this? Problems persist again.

Richard Rublev
  • 857
  • What version of Ubuntu are you running? How did you "upgrade" python? Upgrading the default python version often breaks things. – popey Mar 02 '23 at 08:52
  • @popey 20.04 Ubuntu,I just install python3.9 with pip3 install. I need that for Ansible. – Richard Rublev Mar 02 '23 at 08:53
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    There's usually a symlink from /usr/bin/python3 to whatever the default version is. You could re-create it manually with something like sudo ln -s /usr/bin/python3.8 /usr/bin/python3 to get you out of this hole. – popey Mar 02 '23 at 09:02
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    The default python for your system is python3.8 ... Link it back to python3 as shown in @popey's comment above ... And don't ever alter the default system python version or else that will happen again and it's not always fixable ... So if you managed to fix it with the command above, consider it a lesson learned ... Ubuntu relies on the default system python version ... It's an essential part of the OS and not just an interpreter to run your python scripts. – Raffa Mar 02 '23 at 10:01
  • 1
    Related and might help: https://askubuntu.com/q/1448702 – Raffa Mar 02 '23 at 10:06

0 Answers0