Please tell me how to execute python file in Ubuntu by double

[Christian Gollwitzer]

Am 14.12.17 um 02:55 schrieb Chris Angelico:
> On Thu, Dec 14, 2017 at 12:35 PM, Rick Johnson
> <rantingrickjohnson at gmail.com> wrote:
>> On Tuesday, December 12, 2017 at 10:42:54 PM UTC-6, eryk sun wrote:
>> [...]
>>> That said, I don't see this feature as being very useful
>>> compared to just using "open with" when I occasionally need
>>> to open a file with a non-default program.
>>
>> That's the point i was trying to make, but i think it may
>> have whoooshed over Chris's head. ;-)
> 
> No, it didn't. I just happen to have about twelve years' experience
> with a GUI system that has this as a feature, and I found it extremely
> helpful. It's funny how our experience colours our expectations, isn't
> it? We just won't settle for trash once we've tasted quality.
> 

I'm still unconvinced that this is much different from the Windows way 
(though I haven't used OS/2, so I'm probably missing something):

Suppose, you have a file "Letter.txt" in your Documents folder on 
Windows. With standard settings, the "dumb" user (non IT expert) does 
not see the ".txt". It shows up as "Letter" with an icon for "written 
text". If you double click on it, Notepad will come up. If you right 
click, you'll see a list of programs which can open text files: Notepad, 
Wordpad, MS Word, any other editor you might have installed.

How is the file extension different (to the regular user!) than a file 
type information stored in an alternate stream? Both are normally 
invisible and determine a default application as well as a number of 
programs which can open/edit the file.

The only thing I can see from your description, apparently it was 
possible to change the default for an individual file ("Open this file 
always with Wordpad instead of Notepad") without changing th eglobal 
default. Is this the missing feature?

	Christian