For example, out of about 50 or so /usr/bin/python scripts I see in a RHEL7's /usr/bin I can't find a single one that runs on python3.
No individual user is going to be fixing this. It's a very silly and shortsighted move on RedHat's part.
37 /usr/bin/python3
4 /usr/bin/python3.5
4 /usr/bin/python
3 /usr/bin/python2.7
2 /usr/bin/python2
speedtest, speedtest-cli, dh_python2, apt-offline
So two from ubuntu/debian, and two from a package
Above, we're discussing some build system where someone hasn't done this work. Most collections of python code in the world (I'm going to hazard a guess significantly upward of 90%) just use /usr/bin/python or /usr/bin/env python.
That's the nature of the problem.
> For example, out of about 50 or so /usr/bin/python scripts I see in a RHEL7's /usr/bin
The actual subject is CoolGuySteve's build system, which is likely to look like my example of RHEL7 rather than yours of ubuntu. The vast majority of environments look like RHEL7 or CoolGuySteve's build system where #!/usr/bin/python is the norm.
On RHEL 7 (and earlier) `/usr/bin/python` must be the Python 2 the system shipped with or your break `yum` and other admin tools. When people try to install their own python by doing a `make install` as root, `yum` breaks and it's hard to recover the system.
What the article is saying is that RHEL 8 addresses this by having a platform python that the system tools use. So RHEL 8 tools will not use /usr/bin/python
Offering advice about how to write new software does nothing to help with the frustration he highlighted: His existing build systems will break. Build systems are especially frustrating as they tend to have hacked-together code that no one really wants to look at.
People will often work around this by installing a python2 as /usr/bin/python. At the end of the day this change results in a less predictable platform. On previous RHEL systems I know what /usr/bin/foo is -- it's predictable given the major version of the distro. But now I won't know what /usr/bin/python is on RHEL8. It will be uniquely different and that's not a good thing.