Re: [Tutor] file permissions
> Looking for easiest way to get a files permissions in linux. > look at the os.stat function. I'm in the middle of documenting its use but you might like to peruse the later sections of the following draft topic http://www.freenetpages.co.uk/hp/alan.gauld/tutos.htm Alan G Author of the learn to program web tutor http://www.freenetpages.co.uk/hp/alan.gauld ___ Tutor maillist - Tutor@python.org http://mail.python.org/mailman/listinfo/tutor
Re: [Tutor] file permissions
> > I agree with Danny, the question lacks any evidence of prior
> > investigation on the part of the poster, and that makes it a lousy
> > candidate for the helpful guidance of the python tutor list.
Hi Eric,
It there's something I want to avoid, it's the impression that we're
looking at each question and saying "That's not worthy of our attention."
That's not the real motivation behind asking for more details.
The issue is similar to what typically happens in grade school
when students learn arithmetic. If I see something like:
1 2
- 1 5
-
7
then obviously the student is thinking of something, and doing some sort
of operation in their head. And even if that operation isn't quite right,
at least we can try to figure out why the student's doing addition in some
places, and subtraction in another.
Contrast that transparent situation to another. Imagine seeing a
student's worksheet:
1 2
- 1 5
-
WRONG WRONG WRONG
where we don't get any information at all about what the student was
trying to do.
That silliness is what I'd like to avoid, because that's not how things
work in the real world. We all have partial knowledge, and we know how to
do some things: it's not a binary thing, even if we're dealing with
computer programming.
> I did google and found the same pages that Danny mentioned. Just
> couldn't get the stuff to work, or understand what modules needed to be
> imported to get them to work.
That's information that would have been useful; we'd then concentrate
more on how to filter out the documentation to stuff that's useful to you.
For the programs that was written that didn't work, we'd like to see why
they didn't work: perhaps it might be a misdesign in the module itself,
and perhaps that misdesign can be corrected.
(I know, for example, that Tkinter should do more early error trapping on
its input. For example:
##
>>> Tkinter.Message('hello world')
Traceback (most recent call last):
File "", line 1, in ?
File
"/export/home/dyoo/local/python-2.4//lib/python2.4/lib-tk/Tkinter.py",
line 2634, in __init__
Widget.__init__(self, master, 'message', cnf, kw)
File
"/export/home/dyoo/local/python-2.4//lib/python2.4/lib-tk/Tkinter.py",
line 1856, in __init__
BaseWidget._setup(self, master, cnf)
File
"/export/home/dyoo/local/python-2.4//lib/python2.4/lib-tk/Tkinter.py",
line 1834, in _setup
self.tk = master.tk
AttributeError: 'str' object has no attribute 'tk'
##
There's an error message, but it doesn't really say up front what the real
issue is. It's complaining that 'str' doesn't have the 'tk' attribute,
which is technically true, but what it really should be saying is that the
first argument to Tkinter.Message() has to be a master widget.
But that's something that has a technical fix --- we can modify the
Tkinter.py library to check for that attribute early, and give a good
error message if it see's something wrong. I'm planning to send some
patches later through SF because I know people on Tutor occassionally run
into these bad error messages.)
> > If I may hijack the thread, does anyone more knowledgeable than me
> > know why os.stat and stat are so low-level and esoteric? Am I crazy
> > for wanting to replace
> >
> > oct(stat.S_IMODE(os.stat(thefile)[stat.ST_MODE]))
> >
> > with, say,
> >
> > stat.getmode(os.stat(thefile))
> >
> > or even
> >
> > os.getmode(thefile)
It's possible that no one has considered it a problem yet! *grin*
The design is closely mimicing the interface that C provides us. There's
a case for making it less obscure, but no one has gone through the effort
to make it better yet.
It might make a good project for someone to make grabbing file permissions
a bit nicer.
___
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Re: [Tutor] file permissions
On Wed, Dec 07, 2005 at 02:51:55PM -0700, Eric Walker wrote: > After 4+ hours > of playing around with this I made the futile post. Don't let the post be futile! Post what you've tried so far and you'll get help. gsf ___ Tutor maillist - Tutor@python.org http://mail.python.org/mailman/listinfo/tutor
Re: [Tutor] file permissions
Sorry for the bad question. I did google and found the same pages that Danny mentioned. Just couldn't get the stuff to work, or understand what modules needed to be imported to get them to work. I typically use the tutor list as a last resort. After 4+ hours of playing around with this I made the futile post. On Wednesday 07 December 2005 01:42 pm, Gabriel Farrell wrote: > On Wed, Dec 07, 2005 at 11:52:20AM -0800, Danny Yoo wrote: > > On Wed, 7 Dec 2005, Eric Walker wrote: > > > Looking for easiest way to get a files permissions in linux. > > > > Hi Eric, > > > > What have you looked at so far? > > I agree with Danny, the question lacks any evidence of prior > investigation on the part of the poster, and that makes it a lousy > candidate for the helpful guidance of the python tutor list. The > documentation on this aspect of python, however, is pretty sparse, and > the answer's not exactly intuitive, so I thought I'd mention the > effbot's page about the os module as a good place to look, in addition > to the documentation Danny listed. > > http://effbot.org/librarybook/os.htm > > What he's written there should be able to answer your question. > > If I may hijack the thread, does anyone more knowledgeable than me > know why os.stat and stat are so low-level and esoteric? Am I crazy > for wanting to replace > > oct(stat.S_IMODE(os.stat(thefile)[stat.ST_MODE])) > > with, say, > > stat.getmode(os.stat(thefile)) > > or even > > os.getmode(thefile) > > ? > ___ > Tutor maillist - Tutor@python.org > http://mail.python.org/mailman/listinfo/tutor -- Eric Walker EDA/CAD Engineer Work: 208-368-2573 ___ Tutor maillist - Tutor@python.org http://mail.python.org/mailman/listinfo/tutor
Re: [Tutor] file permissions
On Wed, Dec 07, 2005 at 11:52:20AM -0800, Danny Yoo wrote: > On Wed, 7 Dec 2005, Eric Walker wrote: > > > Looking for easiest way to get a files permissions in linux. > > Hi Eric, > > What have you looked at so far? I agree with Danny, the question lacks any evidence of prior investigation on the part of the poster, and that makes it a lousy candidate for the helpful guidance of the python tutor list. The documentation on this aspect of python, however, is pretty sparse, and the answer's not exactly intuitive, so I thought I'd mention the effbot's page about the os module as a good place to look, in addition to the documentation Danny listed. http://effbot.org/librarybook/os.htm What he's written there should be able to answer your question. If I may hijack the thread, does anyone more knowledgeable than me know why os.stat and stat are so low-level and esoteric? Am I crazy for wanting to replace oct(stat.S_IMODE(os.stat(thefile)[stat.ST_MODE])) with, say, stat.getmode(os.stat(thefile)) or even os.getmode(thefile) ? ___ Tutor maillist - Tutor@python.org http://mail.python.org/mailman/listinfo/tutor
Re: [Tutor] file permissions
On Wed, 7 Dec 2005, Eric Walker wrote: > Looking for easiest way to get a files permissions in linux. Hi Eric, What have you looked at so far? One of the first hits to the Google query "file permission python" comes up with some good information: http://www.faqts.com/knowledge_base/view.phtml/aid/5707/fid/552 Forgive me: I'm giving you a hard time only because it didn't look like you did anything yourself yet. Next time you ask a question, also try to show what you've tried so far to find an answer, so that we know we're not following avenues that you've already pursued. We want to make sure you know how to look for answers. If the existing documentation sucks (and some of Python's documentation does need more work!), then we want to know that too so that we can help improve it by sending comments to the Documentation team. In summary, there's file permission stuff we can extract using the 'stat()' function in the 'os' module: http://www.python.org/doc/lib/os-file-dir.html#l2h-1629 The values we get back from os.stat() are a little obscure, but we can interpret the results using the 'stat' module: http://www.python.org/doc/lib/module-stat.html I'm not sure if there's nicer interface to the permission bits; most material I see on it looks fairly low-level. If you have more questions, please feel free to ask. (But please show what work you've tried so far; that way, we have a better idea of your context.) Good luck! ___ Tutor maillist - Tutor@python.org http://mail.python.org/mailman/listinfo/tutor
