Re: [MacPerl-AnyPerl] recursive delete

[Ronald J Kimball <rjk@linguist.dartmouth.edu>]

On Mon, Jun 28, 1999 at 12:31:29PM -0700, Jeremy Andrews wrote:
> >From owner-macperl-anyperl@cfcl.com  Sun Jun 27 01:13:38 1999 sorry for
> >the delay]
> Message-Id: <v04205102b39b8a65bdbb@[199.165.65.84]>
> In-Reply-To: <199906261100.EAA05753@cfcl.com>
> References: <199906261100.EAA05753@cfcl.com>
> Date: Sun, 27 Jun 1999 00:05:06 -0800
> 
> Hello,
> 
> Is there a good way to recursively delete a directory and all of its
> subdirectories?  I've attempted to do this with the following code,
> but it doesn't work.  (I'm programming this on my Mac, but it's
> intended to work on a Apache UNIX machine...)
> 
> ##########
> # Recursively delete directory
> #	routine is called by passing in a directory to be deleted, in $_[0]
> #
> sub delete_directory {
> 	opendir(DIRECTORY, "$_[0]") or die;

You should include a useful error message when you die.

The quotes around $_[0] are superfluous.


> 	@directories = grep !/\./, readdir DIRECTORY;

You can't have directories with periods in their names?  How curious...


> 	unless (@directories eq "") {

@directories will _never_ eq "".  In a scalar context, an array evaluates
to the number of elements in the array.  This will be 0 if the array is
empty, or a positive integer if the array is not empty, but certainly never
the null string.


> 		foreach $directory (@directories) { delete_directory
> ($_[0]/$directory); }

Take those quotes you used around $_[0] before, and put them around
$_[0]/$directory here.  I really don't think you meant to do a division
here...  :)


Where's the code that checks whether the items in @directories _really
are_ directories?  If you try to delete_directory a file that is not a
directory, then delete_directory will die in the first line.

Hint: You need to use the -d filetest operator.


> 	}
> 	@files = readdir DIRECTORY;

If you want to read from DIRECTORY again, you need to rewinddir() first.
On the other hand, you never localized the dirhandle, so each call to
delete_directory clobbers the previous call's dirhandle.

One solution would be to localize the DIRECTORY glob:
local(*DIRECTORY);

Another would be to reopen the appropriate directory when you need to read
from it a second time.

A third solution would be to read all the names once, and separate them
into two arrays, one for directories and one for files.  Then you won'y
have to read from the dirhandle again.


> 	unlink @files;

You should die if the unlink fails (and include a useful error message).


> 	rmdir $_[0] or die;

You should include a useful error message when you die.


> }
> #
> ##########
> 


Instead of writing the solution from scratch, I would recommend using the
finddepth() function from the File::Find module.


Ronald

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