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From: dmr@research.UUCP
Newsgroups: net.unix-wizards
Subject: null file names
Message-ID: <1040@research.UUCP>
Date: Thu, 13-Sep-84 00:02:20 EDT
Article-I.D.: research.1040
Posted: Thu Sep 13 00:02:20 1984
Date-Received: Fri, 14-Sep-84 21:14:36 EDT
Lines: 20

"If the sequence [of file names] begins with a slash, the search begins
in the root directory.... As a limiting case, the name `/' refers to
the root itself.... A path name not starting with `/' causes the system
to begin the search in the user's current directory.... As another
limiting case, the null file name refers to the current directory."
	-- from the CACM Unix paper, 1974.

Actually, I was considerably annoyed when USG illegalized "" because
it is indeed the natural limiting case, and because (at the time) I could
get no coherent explanation for the change except that some program
had a bug and they preferred to change the semantics of file names
instead of fixing the bug.

The annoyance is lessened now, I suppose because no one actually uses
the null file name (though it makes "." unnecessary).  Also, it has
inconvenient properties under concatenation  (e.g. "" + "/file" = wrong).
And, as I discover while investigating SysV, it sure makes for some
peculiar diagnostics.

				Dennis Ritchie