The problem is that some Linux systems - I think - still use Python2 to
perform various system-related tasks. When they call "python", they
need it to be Python2. If someone has a system like that, they can't
have the "python" command run Python3.
On 11/7/2022 1:07 PM, Schachner, Joseph (US) wrote:
Maybe you can't do this, but I would suggest only running on the Python 3
systems. Refuse to jump through hoops for the Python 2 system. It is years
out of date.
It is not hard to upgrade from Python 2 to Python 3. There is a 2to3 utility,
and after that there should be very few things you want to manually change.
Perhaps you could encourage them to upgrade.
--- Joseph S.
Teledyne Confidential; Commercially Sensitive Business Data
-----Original Message-----
From: Chris Green <c...@isbd.net>
Sent: Monday, November 7, 2022 4:06 AM
To: python-list@python.org
Subject: Re: How to manage python shebang on mixed systems?
Cameron Simpson <c...@cskk.id.au> wrote:
On 06Nov2022 20:51, jak <nos...@please.ty> wrote:
Il 06/11/2022 11:03, Chris Green ha scritto:
I have a number of python scripts that I run on a mix of systems. I
have updated them all to run on python 3 but many will also run
quite happily with python 2. They all have a #!/usr/bin/python3 shebang.
I usually use:
#!/usr/bin/env python3
This runs the default "python3" from my $PATH, whatever that is,
avoiding a hardwired path to the python3 executable.
Yes, that's probably a good idea, less likely to break than mine.
This works almost everywhere but there is one system where only
python 2 is available (at /usr/bin/python).
I don't have python 2 on any of the systems I manage myself now so a
#!/usr/bin/python shebang will fail.
Is there a neat way of handling this? I could write a sort of
wrapper script to run via the shebang but that seems overkill to me.
It is overkill. I generally dislike batch editing scripts.
1: do these scripts work on both python2 and python3? It seems like
they would need to.
Yes, they do, they're mostly very simple utility scripts for doing things like
changing spaces to underscores in filenames and such.
Just putting 'print' parameters in brackets was all that most of them needed to
work in python 3.
2: write a tiny script _named_ "python3" which invokes python 2. I
keep a personal "~/bin-local" directory for just such per-system
special commands like this.
3: with your pseudo "python3" script in place, make all the scripts
use the "#!/usr/bin/env python3" shebang suggested above.
Yes, that sounds a good plan to me, thanks Cameron.
--
Chris Green
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