Comparison function for directories?

Hi,

I'm using php 4.4.4. Given two variables,

$dir1 = "/usr/local/apache2/htdocs/"
$dir2 = "/usr/local/apache2/htdocs"

What is a comparison function I could write that would say these two
directories are the same? A straight string comparison would not work
above.

Thanks for any insights, - Dave

On Thu, 28 Feb 2008 18:57:11 +0100, laredotornado@zipmail.com
<laredotornado@zipmail.com> wrote:

> Hi,
>
> I'm using php 4.4.4. Given two variables,
>
> $dir1 = "/usr/local/apache2/htdocs/"
> $dir2 = "/usr/local/apache2/htdocs"
>
> What is a comparison function I could write that would say these two
> directories are the same? A straight string comparison would not work
> above.

$is_the_same_dir = realpath($dir1) == realpath($dir2);
--
Rik Wasmus

*** Rik Wasmus escribió/wrote (Thu, 28 Feb 2008 19:00:09 +0100):
>> $dir1 = "/usr/local/apache2/htdocs/"
>> $dir2 = "/usr/local/apache2/htdocs"
>>
> $is_the_same_dir = realpath($dir1) == realpath($dir2);

Just two remarks:

- In Unix, the file system is case sensible. So (depending on what you need
this for) you may use === instead.

- realpath() returns FALSE when the path does not exist; take it into
account.


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--

�lvaro G. Vicario wrote:
> Rik Wasmus escribió/wrote:
>>
>> $is_the_same_dir = realpath($dir1) == realpath($dir2);
>
> - In Unix, the file system is case sensible. So (depending on what you
> need this for) you may use === instead.

The '==' operator is sufficient, as it is case-sensitive. The '===' will
also work, but is not required.

> - realpath() returns FALSE when the path does not exist; take it into
> account.

This may indeed cause problems, depending on exactly what the OP is hoping
to compare -- the directory paths of real, existing directories, or
strings representing directories which may or may not exist.

A possibility would be to replace realpath above with normalise_dirname:

function normalise_dirname ($dir)
{
if (realpath($dir))
return realpath($dir);
if (preg_match('#/$#', $dir))
return $dir;
return "$dir/";
}

If you needed to, you could further enhance it to deal with path
components like '.' and '..'.

--
Toby A Inkster BSc (Hons) ARCS
[Geek of HTML/SQL/Perl/PHP/Python/Apache/Linux]
[OS: Linux 2.6.17.14-mm-desktop-9mdvsmp, up 30 days, 22:28.]

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