On 2019-07-21 09:04:43 +1000, Cameron Simpson wrote: > On 21Jul2019 08:14, Chris Angelico <[email protected]> wrote: > > On Sun, Jul 21, 2019 at 5:26 AM Tim Daneliuk <[email protected]> wrote: > > > So, no, do NOT encode the hard location - ever. Always use env to > > > discover the one that the user has specified. The only exception > > > is /bin/sh which - for a variety of reasons - can reliably counted > > > upon. > > > > A quick grep through my $PATH shows that there are a number of > > executable Python scripts there, including add-apt-repository, > > calibre, some lilypond stuff, trash-can management, samba-tool, iotop, > > and youtube-dl. If I have a venv active with, say, Python 3.9, then > > `/usr/bin/env python` is going to point to Python 3.9. What are the > > odds that all those scripts will work with Python 3.9 with no > > libraries installed? Why should typing "youtube-dl B7xai5u_tnk" be > > affected by a virtual environment, when typing "man youtube-dl" > > wouldn't be?? Using env for everything is a terrible idea and one that > > will basically make virtual environments useless. > > I'm with Tim Daneliuk. The environment matters and should be honoured except > in extremely weird cases.
I don't think that all the scripts in /usr/bin are extremely weird
cases.
> If you require a specific outcoming, set a specific environment. It is under
> your control. Control it.
>
> For your specific example, "man youtube-dl" _is_ affected by the
> environment. It honours the $MANPATH variable.
MANPATH is explicitely intended to control man.
But man doesn't fail if you set your PATH to something weird. It will
still invoke /usr/bin/groff even if that isn't in the PATH.
(I expected that there is also an environment variable to control that
but the manpage doesn't mention one).
> For Peter J. Holzer, if we must play the "I've been doing this forever"
> game: I've been sysadmining etc longer than your 25 years and disagree with
> you.
That's fine. Unlike Tim I don't claim that anybody who disagrees with me
must be a newbie.
hp
--
_ | Peter J. Holzer | we build much bigger, better disasters now
|_|_) | | because we have much more sophisticated
| | | [email protected] | management tools.
__/ | http://www.hjp.at/ | -- Ross Anderson <https://www.edge.org/>
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