Path: utzoo!mnetor!uunet!longway!std-unix
From: jc@minya.UUCP (John Chambers)
Newsgroups: comp.std.unix
Subject: Re: Standards Update (3 of 4): NBS FIPS
Message-ID: <130@longway.TIC.COM>
Date: 15 Feb 88 20:44:05 GMT
References: <116@longway.TIC.COM> <120@longway.TIC.COM>
Sender: std-unix@longway.TIC.COM
Reply-To: jc@minya.UUCP (John Chambers)
Organization: home
Lines: 38
Summary: Is rename() guaranteed to work across directories?
Approved: jsq@longway.tic.com (Moderator, John S. Quarterman)

From: jc@minya.UUCP (John Chambers)

[ This one got misplaced as I prepared to go to USENIX.
I don't really understand the question, but if it's whether the
rename function can be used to move directories, the answer is yes
(although the user command is mv).  -mod ]


> >No portable application needs "appropriate privileges" to move directories
> >around; it can use "rename()".  The correct way to move anything under a POSIX
> >implementation is to use "rename()", not "link()" and "unlink()".
> 
> The rename() call is sufficient for changing the name of a directory, ...

One thing I've wondered is whether the standard will require implementors
to make things like rename("foo/bar/x","foo/x") work correctly.  This is
a serious omission in a great many Unix releases.

It's not at all a hypothetical issue.  I've seen a lot of cases where
a user (myself included) uses tar or cpio or some such to unpack a bunch
of files, intending them to go into foo/bar, and ending up with them all 
in foo/bar/bar.  The usual result is "rm -rf foo/bar/bar" and starting 
over.  It'd save a lot of grief if one could just say something like:
	rename foo/bar/bar foo/temp
	rename foo/temp foo/bar
and be done with it.  Of course, it'd be better if I could just type:
	rename foo/bar/bar foo/bar
and get the desired result, but that's probably too much to hope for. ;-)

Given the history of Unix releases, I wouldn't expect this to work when 
foo/bar/bar is a directory, unless there is some argument stronger than 
users' needs to convince the implementors.

-- 
John Chambers <{adelie,ima,maynard,mit-eddie}!minya!{jc,root}> (617/484-6393)


Volume-Number: Volume 13, Number 16