Yes,
`Sys.readlink` is returning values as explained/expected.
I was very confused by mixing C library functions with coreutils and not
reading careful enough, please excuse me for that.
A link to `normalizePath` would be of help in the 'See Also' section, in my
opinion.
Regards,
Sven
> On 29 Feb 2016, at 16:02, Simon Urbanek <simon.urba...@r-project.org> wrote:
>
>
>> On Feb 29, 2016, at 5:59 AM, Sven Templer <sven.temp...@gmail.com> wrote:
>>
>> Hello,
>>
>> sorry for not being clear enough.
>>
>> My problem is represented with the following code, running on OSX:
>>
>> mkdir ~/test
>> ln -s ~/test ~/testlink
>> touch ~/test/foo
>> Rscript -e 'Sys.readlink(c("~/test/foo", "~/testlink/foo"));
>> normalizePath(c("~/test/foo","~/testlink/foo"))'
>>
>> I expected `Sys.readlink` to show the same output as `normalizePath`.
>
>
> Why? To quote from the Sys.readlink() docs:
>
> Value:
>
> A character vector of the same length as ‘paths’. The entries are
> the path of the file linked to, ‘""’ if the path is not a symbolic
> link.
>
> since you are referring to a file and not a link the result is as expected ""
> - both on OS X and Linux.
>
>
>> Also, I think the readlink.h imported to R to be the same as from the
>> system's `readlink` command, thus mimicking the command line difference.
>>
>> Am I wrong with the latter? Anyway, the behaviour is irritating, thus the
>> request to at least mention `normalizePath` in the Rd of `Sys.readlink`.
>>
>> Best,
>> Sven
>>
>>
>>> On 29 Feb 2016, at 11:44, Mikko Korpela <mikko.korp...@aalto.fi> wrote:
>>>
>>> On 29.02.2016 10:34, Sven E. Templer wrote:
>>>> Hello together,
>>>>
>>>> the function `Sys.readlink` uses the system's readlink command to resolve
>>>> symlink paths. On OSX/BSD the command has a different meaning than on
>>>> Linux [1].
>>>>
>>>> There exists the tool 'realpath', which seems suitable for the task, at
>>>> least applied at the command line level [2]. It is used in `normalizePath`.
>>>>
>>>> I suggest (at least the latter) to
>>>> * use realpath instead readlink within Sys.readlink (do_readlink ->
>>>> do_normalizepath)
>>>> * link to `normalizePath` in the Rd document, eventually mentioning the
>>>> difference
>>>>
>>>> Many thanks,
>>>> Sven
>>>>
>>>> [1] see
>>>> https://www.freebsd.org/cgi/man.cgi?query=readlink
>>>> vs
>>>> http://linux.die.net/man/1/readlink
>>>>
>>>> [2]
>>>> https://www.freebsd.org/cgi/man.cgi?query=realpath
>>>> http://linux.die.net/man/1/realpath
>>>
>>> What do you mean by "different meaning"? How are the command line tools
>>> [1] relevant when R is using the C function 'readlink'?
>>>
>>> http://pubs.opengroup.org/onlinepubs/9699919799/functions/readlink.html
>>> https://www.freebsd.org/cgi/man.cgi?query=readlink&sektion=2
>>> http://man7.org/linux/man-pages/man2/readlink.2.html
>>>
>>> --
>>> Mikko Korpela
>>> Aalto University School of Science
>>> Department of Computer Science
>>
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>>
>
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