Python shebang policy

Gary E. Miller gem at
Tue Mar 20 21:24:06 UTC 2018

Yo Richard!

On Tue, 20 Mar 2018 15:48:37 -0500
Richard Laager via devel <devel at> wrote:

> On 03/20/2018 02:58 PM, Gary E. Miller via devel wrote:
> > How does it handle multiple Pythons at the same time?  
> Python is a specific example of the generalized problem of wanting two
> different versions of the same software installed at the same time.
> That generalized problem is solved by versioning executable names (and
> anything else necessary, like config/library directories).
> /usr/bin/python  is Python 2
> /usr/bin/python3 is Python 3

Two?  gentoo can trivially handle more than 7.

> More specifically, these are symlinks to, for example, /usr/python/2.7
> and /usr/bin/python3.5.

Way more complex in gentoo.  I suspect in other distros as well.

> It's thus possible to have multiple minor
> versions of the same major version installed. I haven't paid close
> attention, but I'd imagine that scenario only exists during minor
> version transitions and not in a released version of Debian.

Just looked at an Ubuntu install, it has three minor versions installed.

> For more reading:

I'll leave the denian to you.

> The ntpsec package patch is just changing:
> #!/usr/bin/env python
> to:
> #!/usr/bin/python3

Yeah, which just breaks Gentoo.  So, once again, FAIK, have at if this
is an installer selected non-default option, just do not make it the
default as that breaks things.

> If ntpsec was setting the shebang lines from a configure parameter, I
> could use that and avoid the patch. This would be cleaner. But, it's
> not like the patch is that big of a deal either.

Not sure why we are still discussing it, if you want a non-default
installer option, I've not heard any objection so far.

Just do not make it default, and don't break current --python behavior.

Gary E. Miller Rellim 109 NW Wilmington Ave., Suite E, Bend, OR 97703
	gem at  Tel:+1 541 382 8588

	    Veritas liberabit vos. -- Quid est veritas?
    "If you can’t measure it, you can’t improve it." - Lord Kelvin
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