On 01/30/2012 10:22 PM, Eric Blake wrote: > On 01/30/2012 03:01 PM, Pádraig Brady wrote: >>> $ realpath --relative-to=// //machine / // /bin >>> machine >>> / >>> . >>> /bin >>> >>> We need to make realpath robust to correct leading // handling; I don't >>> know if we should follow the lead of 'dirname' in only doing it on >>> machines where // is special, or if it is easier to make it honor POSIX >>> by special-casing // everywhere even on machines where / and // are >>> identical. >> >> So on such a machine, I guess `readlink -m //machine/` outputs '//machine'. > > Correct. > >> To match up with that, I think it makes sense to only do this on systems >> where a double slash is significant. > > I'm tending to agree - readlink, dirname, and realpath should all behave > consistently within a single compilation of coreutils. > >> >> BTW, this is how I'm interpreting this example: >> >>> $ realpath --relative-to=// //machine / // /bin >>> machine >>> / >>> . >>> /bin >> >> I'm taking --relative-to=// to mean relative to "the network". >> Hence relative output will be machines on the network, >> while absolute are local paths. > > Correct. > > Another bug still in the latest coreutils.git, but only on platforms > with distinct //: > > $ src/realpath / // /// > / > // > // > > Oops, that last line should be /. This bug is shared by readlink: > > $ src/readlink -m /// > //
The above will require a gnulib fix >> gnulib says // matters for Apollo DomainOS (too old to port to), >> Cygwin, and z/OS. > > And I tested on Cygwin (if it wasn't obvious :) > > I can try to develop patches as part of porting coreutils 8.15 to cygwin I'll take you up on that, thanks! > (cygwin already has a realpath(1), but it is severely limited in that it > only takes one file name and no command line options on what to do with > that name; I'm pretty sure that the coreutils realpath is upwards > compatible with the existing cygwin realpath: > http://cygwin.com/ml/cygwin-apps/2012-01/msg00080.html). I had a look at the source, and it's just a simple wrapper around realpath(), that only accepts a single path. So coreutils realpath should be a drop in replacement. (wow it's hard to navigate cygwin stuff. It took me 3 mins to find the latest source). cheers, Pádraig.
