Phantom directories created using mkdir

jonnyfolk has asked for the wisdom of the Perl Monks concerning the following question:

I am using mkdir to create a directory:

$dir_name = "/path/$scalar";
mkdir $dir_name, 0777 unless -d $dir_name;
[download]

On occasions this created false directories on the occasions that $scalar wasn't available. I used a conditional to prevent this:

if ($scalar) {
$dir_name = "/path/$scalar";
mkdir $dir_name, 0777 unless -d $dir_name;
}   else { die "Sorry, no scalar value available: $!"
    }
[download]

However I see that phantom directories are still being created (with the name $scalar). On trying to open the directories I get "server response: no such file".

How can I prevent this happening an what can I do to remove these 'phantom' files?

Comment on Phantom directories created using mkdir Select or Download Code

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Re: Phantom directories created using mkdir by jasonk (Parson) on Feb 19, 2003 at 16:34 UTC
Something else is happening in your code that isn't demonstrated here, the only way you could get a directory named '$scalar' is if either you used single quotes when creating $dir_name, preventing the variable from getting interpolated, or the variable $scalar contains the word $scalar. If $scalar were simply empty, the code you have here would be checking /path/ and not creating the directory. If this is a unix machine you should be able to remove that directory by using `rm ./\$scalar`, or `perl -e "unlink('$scalar');"`	[reply] [d/l] [select]
Re: Re: Phantom directories created using mkdir by jonnyfolk (Vicar) on Feb 19, 2003 at 17:01 UTC
I'm sorry - I've obviously been more than usually obtuse in the phrasing of this question. when I wrote that the directory is named $scalar I meant that the scalar $scalar had interpolated properly and had been given its correct name. Thus if $scalar=1000 , the directory would be found at /path/1000 As for deleting the 'phantom' directories - the problem is that the (Unix) server states that they don't exist! I can see them via my ftp client.	[reply]
Re: Phantom directories created using mkdir by CountZero (Bishop) on Feb 19, 2003 at 16:32 UTC
To get a better understanding of your question, what do you mean by "the occasions that $scalar wasn't available"? Do you mean that $scalar was empty or undef or not yet existing or not in this scope or ... ? CountZero "If you have four groups working on a compiler, you'll get a 4-pass compiler." - Conway's Law	[reply]
Re: Re: Phantom directories created using mkdir by jonnyfolk (Vicar) on Feb 19, 2003 at 16:52 UTC
I mean that $scalar was undefined. This was actually due to a faulty line of code where $scalar wasn't being passed properly. I fixed that problem but left the conditional in place as insurance!	[reply]
Re: Phantom directories created using mkdir by OM_Zen (Scribe) on Feb 19, 2003 at 16:39 UTC
Hi , The $scalar , is it defined using a my (should be) you should use like `if ($scalar ne ""){ $dir_name = "/path/$scalar"; mkdir $dir_name, 0777 unless -d $dir_name; }else{ # print " the error and exit $! \n"; }` [download] As I have only this part of your total post , I guess you are checking for the definition rather than the value of the scalar variable	[reply] [d/l]
Re: Re: Phantom directories created using mkdir by jonnyfolk (Vicar) on Feb 19, 2003 at 17:08 UTC
Yes, absolutely. I can see that what you are suggesting is better than what I had and will incorporate it. thanks for your help.	[reply]