[TUHS] moving directories in svr2

[Brantley Coile]

Plan 9 can't move directories with mv. I will only change the name of them.
(If this is the question. I was only half paying attention to the thread. Sorry)

	--bwc

cessna% mkdir dira
cessna% mkdir dirb
cessna% touch dira/a
cessna% touch dirb/b
cessna% mv dira dirb
mv: can't remove ./dirb: remove -- directory not empty

To move contents of directories we use dircp.

cessna% man dircp

     TAR(1)                                                     TAR(1)

     NAME
          tar, dircp - archiver

     SYNOPSIS
          tar key [ file ... ]

          dircp fromdir todir

     DESCRIPTION
          Tar saves and restores file trees.  It is most often used to
          transport a tree of files from one system to another.  The

 	...
               and .tz.  If no extension matches, gzip is used.  The z
               flag is unnecessary (but allowed) when using the t and
               x verbs on archives with recognized extensions.

     EXAMPLES
          Tar can be used to copy hierarchies thus:

               @{cd fromdir && tar c .} | @{cd todir && tar xT}

          Dircp does this.

     SOURCE
          /sys/src/cmd/tar.c
          /rc/bin/dircp

     SEE ALSO
          ar(1), bundle(1), tapefs(4), mkfs(8)



cessna% 
> On Dec 29, 2021, at 12:38 PM, Clem Cole <clemc at ccc.com> wrote:
> 
> At the risk of kicking a dead horse too much ...
> 
> On Wed, Dec 29, 2021 at 12:14 PM <arnold at skeeve.com> wrote:
> Plan 9 eventually did something like this. I don't remember the details.
> Arnold - point taken but ... unfortunately, I think that the comparison is a little difficult because Plan9's concepts of namespaces is a tad different than UNIX's.  But I'll let Rob or Ken comment as they lived and developed both systems.
> 
> FWIW: An object store is something that retains information after the processes that operates on it complete - i.e. its a static entity.  Links were (are) also a static concept.   Late binding to names (like symlinks) are a dynamic (runtime idea).  Bakul points out that by using the per process u area, the dynamic context can be retained.  The observation is that .. (like symlinks) tend to be a runtime (dynamic) notion, although I'm not sure how you keep consistency in the static FS if you don't store the link in the inode.  As someone that did, I suggest - try writing fsck if you are using dynamic content.   How do you know?  I'd still claim it is the same issue.
> 
> Anyway, I suppose that like context sensitive symlinks (which I sorely miss), you could do this and keep a list of the N inodes for the N parents and then like CDSL's keep the one you used to get there in the u area so that .. picks the proper one on the way out and you can still have the static notion which something like fsck can check off line.