How to get the realpath of a symbolic link?

[Peng Yu]

On Sat, Oct 31, 2009 at 1:46 PM, Terry Reedy <tjreedy at udel.edu> wrote:
> Peng Yu wrote:
>>
>> On Sat, Oct 31, 2009 at 11:26 AM, Emile van Sebille <emile at fenx.com>
>> wrote:
>>>
>>> On 10/31/2009 12:03 AM Peng Yu said...
>>>>
>>>> Suppose that I have the following directory and files. I want to get
>>>> the canonical path of a file, a directory or a symbolic link.
>>>> For example, for 'b' below, I want to get its canonical path as
>>>> '/private/tmp/abspath/b'.
>>>
>>> So, why isn't realpath working for you?  It looks like it is, and it
>>> works
>>> that way here:
>>>
>>>>>> os.path.realpath('/home/emile/vmlinuz')
>>>
>>> '/root/vmlinuz-2.4.7-10'
>>
>> My definition of 'realpath' is different from the definition of
>> 'os.path.realpath'. But I'm not short what term I should use to
>> describe. I use the following example to show what I want.
>>
>> In my example in the original post,
>>
>> '/tmp/abspath/b' is a symbolic link to '/tmp/abspath/a' and '/tmp' is
>> a symbolic link to '/private/tmp'.
>>
>> Therefore, I want to get '/private/tmp/abspath/b', rather than
>> '/private/tmp/abspath/a', as the canonical path of 'b'.
>>
>> If the argument is a symbolic link os.path.realpath will return the
>> actually target of the symbolic link. However, I want the path of the
>> symbolic link rather than the path of the target.
>>
>> Hope this is clear.
>
> I suspect that you will have to write your own code for your own function.
> os and os.path are written in Python, so look at the code for realpath and
> modify it for your modified definition.

I find the following two files that define realpath. But I don't find
'realpath' in os.py. I looked at 'os.py'. But I don't understand how
the function realpath is introduced in the name space in os.path.
Would you please let me know?

gfind . ! -path '*backup*' -name "*.py" -type f -exec grep -n "def
realpath" {} \; -printf %p\\n\\n
193:def realpath(path):
./macpath.py

345:def realpath(filename):
./posixpath.py