Chris Angelico wrote: > On Tue, Jan 31, 2017 at 12:58 AM, Peter Otten <__pete...@web.de> wrote: >>> I looked at help(os.link) on Python >>> 3.4 and the corresponding current library documentation on the web. I >>> saw no mention of what happens when dst exists already. >>> >>> Also, creating a hard link doesn't seem to work between different file >>> systems, which may well be relevant to Steve's case. >> >> In his example above he operates inside a single directory. Can one >> directory spread across multiple file systems? > > Yep. Try unionfs. > > ... make ourselves some scratch space ... > $ mkdir space modifier > $ dd if=/dev/zero of=space.img bs=4096 count=65536 > $ mkfs space.img > $ sudo mount space.img space > $ dd if=/dev/zero of=modifier.img bs=4096 count=1024\ > $ mkfs modifier.img > $ sudo mount modifier.img modifier > > ... put some content into the base directory ... > $ sudo -e space/demo.txt > > ... and now the magic: > $ unionfs modifier=RW:space=RO joiner/ > $ cd joiner > > At this point, you're in a directory that is the union of the two > directories. One of them is read-only, the other is read/write. It is > thus possible to view a file that you can't hard-link to a new name, > because the new name would have to be created in the 'modifier' file > system, but the old file exists on the 'space' one.
Interesting example, thanks! -- https://mail.python.org/mailman/listinfo/python-list
