Python binary not found on Ubuntu

[Tuupertunut]

Udocker version: 1.3.8

How to reproduce:

• Have Ubuntu 22.04.
• Download Udocker 1.3.8 from the releases section.
• Run udocker --version.
• Observe the following error:

  user@machine:~/udocker$ ./udocker --version
  /usr/bin/env: ‘python’: No such file or directory

Why this happens

The file https://github.com/indigo-dc/udocker/blob/master/udocker/maincmd.py starts with #!/usr/bin/env python. There is usually no binary called python on modern Ubuntu. Changing that line to #!/usr/bin/env python3 works.

[mariojmdavid]

hi the point is that other distros such as almalinux 9, python is already link to python3 by default furthermore we are still supporting udocker in older distros, where we have python(2)

until we drop support for python2, (this will happen in the next major version), we will have to keep the #!/usr/bin/env python

for ubuntu22.04 the solution is either to

apt install python-is-python3

or modify maincmd.py to have

!/usr/bin/env python3