Installation hell

[Chris Angelico]

On Tue, 20 Dec 2022 at 03:05, Thomas Passin <list1 at tompassin.net> wrote:
>
> That's not been my experience.  Windows installers for Python have
> worked well for me over many generations of Python releases.  It's Linux
> where I've found difficulties.  For example, if your distro's Python
> install didn't include tkinter (or even pip), how do you get it?  It's
> different for different Linux distros.  I generally have to use internet
> searches to find out.

If you want to use your distro's Python and add more stuff to it
globally, then yes, it depends on your distro. This is not really a
surprise.

> For another example, when you use pip to install a package, it sometimes
> suggests that you install a newer version of pip itself. Should you do
> that?  On Linux, probably not, because the distro will have modified pip
> so it puts things in distro-specific places. Yet there is no newer
> version of pip available through the distro's package manager.  Will
> anything bad happen if you don't update pip?  Who knows?

Virtual environments work the same way regardless of distro, including
allowing you to install an upgraded pip. As long as your distro
provides the venv package (on Debian, that's in python3-venv), you can
just:

$ python3 -m venv env
$ source env/bin/activate
$ pip install -U pip
$ pip install -r requirements.txt
$ pip install some-package-name
$ etc etc etc etc etc

This is also a recommended way to do things on Windows, so you don't
even need to do things differently.

> I have a Linux VM that has several versions of Python3 on it.  Python3.8
> came installed with the distro, but for some programs I need Python
> 3.9+.  If I forget which versions I have, how can I find out?  People
> say to use which, but that doesn't work - it only reports "python3".
> This does work, but it's not all that easy to remember (the grep "site"
> part is just to filter out uninformative result lines):

Use what your shell already offers you! If you have multiple Pythons
installed, type "python3" and hit tab twice. You should get a list of
options. The exact shell you're using will affect how they're shown,
but I'm pretty sure most shells (at least, the ones designed to be
interactive - /bin/dash might not) will give you some facility like
this.

rosuav at sikorsky:~$ python3
python3               python3.5-dbg-config  python3.8-config
python3.10            python3.5dm           python3.8m
python3.10-config     python3.5dm-config    python3.8m-config
python3.11            python3.5m            python3.9
python3.11-config     python3.5m-config     python3.9-config
python3.12            python3.6             python3.9d
python3.12-config     python3.6-config      python3.9-dbg
python3.4             python3.6m            python3.9-dbg-config
python3.4-config      python3.6m-config     python3.9d-config
python3.4m            python3.7             python3-config
python3.4m-config     python3.7-config      python3d
python3.5             python3.7m            python3-dbg
python3.5-config      python3.7m-config     python3-dbg-config
python3.5-dbg         python3.8             python3d-config
rosuav at sikorsky:~$ python3

Yes, this is a bit noisy in that it has the -config and -dbg-config
tools listed as well, but you can easily see all the variants that are
installed.

> ~$ find 2>/dev/null ~ -name python -type d |grep "site"
> /home/tom/.local/lib/python3.9/site-packages/PyQt5/Qt5/qsci/api/python
> /home/tom/.local/lib/python3.8/site-packages/pandas/_libs/src/ujson/python
> /home/tom/.local/lib/python3.10/site-packages/PyQt5/Qt5/qsci/api/python

Ugh, that's a horribly inefficient way to do it. All you need to do is
search $PATH. If tab completion isn't suitable, you could probably use
"whereis python3", though it's probably a bit noisy.

> Not that this task is much easier to remember on Windows, but it's not
> harder.  One way: the "py" launcher will tell you:
>
> py --list
> -V:3.10 *        Python 3.10 (64-bit)
> -V:3.9           Python 3.9 (64-bit)
> -V:3.7           Python 3.7 (64-bit)
> -V:2.7
>
> This is not Linux-bashing, but there's no need for Windows-bashing either.

There's no need for Linux-bashing when Linux isn't the problem. :)

And Windows wasn't the OP's problem. Nor was Python. The OP moaned
about a lack of IDEs, when pretty much every IDE and text editor out
there has Python support.

We're not here to bash anything. Well, except maybe the popular Unix
shell. I'll /bin/bash that every day of the week... ahem. Anyhow.
We're here to share tips and help everyone be more productive.

ChrisA