Proper shebang for python3

[Chris Angelico]

On Sun, Jul 21, 2019 at 3:41 AM Manfred Lotz <ml_news at posteo.de> wrote:
>
> Hi there,
> Pretty new to python I've got a question regarding the proper shebang
> for Python 3.
>
> I use
>    #!/usr/bin/python3
>
> which works fine.
>
> Today I saw
>    #!/usr/bin/python3 -tt
>
> and was wondering what -tt means.
>
> Being on Fedora 30, Python 3.7.3 the man page of python3 doesn't even
> mention -t.
>
> python 2 man page mentions
>
>        -t     Issue a warning when a source file mixes tabs and spaces
>        for indentation in a way that makes  it  depend  on  the worth
>        of a tab expressed in spaces.  Issue an error when the option is
>        given twice.
>
> I guess that -t has the same meaning with python 3.7.3.

Far as I know, the -tt option to Python 3 is accepted for 2/3
compatibility, but does absolutely nothing. Having it on the shebang
probably means that it used to be /usr/bin/python -tt, and got
migrated to python3 without removing it.

ChrisA