Very Computer

This created $HOME/filename !?

date > $HOME///////filename

No common sense reason for this has occurred to me.

Quote:>This created $HOME/filename !?
>date > $HOME///////filename
>No common sense reason for this has occurred to me.

It means that your programs can do things like:

  printf(Enter directory name: ");
  gets(file_name);
  strcat(file_name, "/basename");

Whereas in DOS you wind up doing:

  printf(Enter directory name: ");
  gets(file_name);
  if (file_name[strlen(file_name) - 1] == '\\')
        strcat(file_name, "basename");
  else
        strcat(file_name, "\\basename");

Actually it's worse since both slash and backslash are acceptable so you
really have to test for both.

If directory separators didn't collapse then what would "$HOME/////filename"
mean?

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Quote:>This created $HOME/filename !?
>date > $HOME///////filename
>No common sense reason for this has occurred to me.

Well, in the typical unix tradition, this has mutated into
    date > $HOME/././././././filename

However, most of the kernel's that I have seen all strip multiple '/' within
the middle of a pathname.

Several versions of "unix" treat leading double shashes "//foo" as a special
case.  Examples of these are Domain OS (Apollo) and older versions of UTek
(Tektronix, rip)

        -Jeff
--

I am rather curious as to what special case "//foo" would signal?

James Risner

Quote:

>This created $HOME/filename !?

>date > $HOME///////filename

>No common sense reason for this has occurred to me.

WHAT did you expect anyway? Anything else happening would make less sense
I think, except may be an error message.

Peter

The Posix standard (see sections 2.3 and 2.4) requires that multiple
slashes in a pathname be interpreted as a single slash.  The one
exception to this is when the path begins with slash.  In that one
case, is it permitted for an implementation to give special meaning to
a pathname that begins with exactly two slashes.  This is how some
Unixes implement remote file systems.  For example,
//remotehost/usr/local/foo might be the file /usr/local/foo on the
machine named remotehost.  Any other use of multiple slashes, such as
////remotehost/usr/local/foo or /usr////////////local/foo must be
treated as though there were one slash.

This behavior is reasonable and desirable.  On more than one
occasion, I've used a command such as

% mv f1 foo/bar/baz     # baz is a directory, so file will be foo/bar/baz/f1

to move a file into a new directory without changing it's name.
Now, if I do this and misspell "baz", then instead of putting the
file in the directory foo/bar/baz, I end up with a file named
foo/bar/bax, or something like that.  After doing this enough times,
I've gotten in the habbit of ALWAYS putting a slash at the end of
directory names in such cases.

% mv f1 foo/bar/baz/

Now if I misspell baz, the mv will fail, since the directory
foo/bar/bax doesn't exist.  When I do spell baz correctly, mv almost
surely generates the target pathname internally as foo/bar/baz//f1,
so this trick of mine will only work if multiple slashes are treated
sensibly.  This does NOT work under DOS...

% COPY F1.C SOURCE\

will barf.  Stupid DOS.

Jim
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Quote:>I am rather curious as to what special case "//foo" would signal?

In Domain/OS and, I think, some other systems, "//foo/bar" was "file
named 'bar' in the root directory of the machine named 'foo'".

The double slash in UTek means a host on the same network with
you. So, it means that you can

cp *.c //r2d2/usr/local/src/foo.

to copy files from wherever you are to /usr/local/src/foo
on host, r2d2. You can also:

cd //r2d2/usr/users/foo

and

//c3p0/usr/local/bin/ispell foobar.
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          Dan Flak - Just another idiot, born in the USA and over 35.