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`.
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.korpela at 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
> On 29 Feb 2016, at 11:59, Sven Templer <sven.templer at gmail.com> wrote: > > 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.Please ignore this statement, sorry.
> On Feb 29, 2016, at 5:59 AM, Sven Templer <sven.templer at 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.korpela at 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 > > ______________________________________________ > R-devel at r-project.org mailing list > https://stat.ethz.ch/mailman/listinfo/r-devel >
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.urbanek at r-project.org> wrote: > > >> On Feb 29, 2016, at 5:59 AM, Sven Templer <sven.templer at 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.korpela at 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 >> >> ______________________________________________ >> R-devel at r-project.org mailing list >> https://stat.ethz.ch/mailman/listinfo/r-devel >> >