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

I've written a script that, at one point, creates a temporary directory, creates a symlink of a file in that directory, then does some other stuff. After performing some unrelated stuff, it uses unlink to delete the symlink. Or, that's what I was hoping would happen. Instead, unlink reports in $! that the file does not exist. Here's a snippet from my code: 

# This part works beautifully...

$pathToFiles = '/home/pencilneckgeek/files';
$tempDir = '/home/pencilneckgeek/tmp/' + random(10000);

mkdir($tempDir) or die "mkdir: $!\n";

$origFile = "$pathToFiles/theFile.txt";
$theLink  = "$tempDir/theFile.txt";

symlink($origFile, $theLink) or die "symlink: $!\n";

# do some stuff...
...
# now, here's where the problem lies...

unlink($theLink) or die "unlink: $!";

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which dies at the unlink, reporting "unlink: No such file or directory" $theLink doesn't change at all at any point in the code - the file's path/name is simply sent off to another program (which currently does nothing)... Any ideas?

Replies are listed 'Best First'.
Re: unlink unworking
by chromatic (Archbishop) on May 17, 2000 at 06:02 UTC
    I had to make a few changes to get this to compile, but when I did it worked correctly: 
    #!/usr/bin/perl -w

use strict;

my $pathToFiles = '/home/pencilneckgeek/files';
my $tempDir = '/home/pencilneckgeek/tmp' . rand(10000);

mkdir($tempDir, 0777) or die "mkdir: $!\n";

$origFile = "$pathToFiles/theFile.txt";
$theLink  = "$tempDir/theFile.txt";

symlink($origFile, $theLink) or die "symlink: $!\n";

  # do some stuff...
  ...
  # now, here's where the problem lies...

unlink($theLink) or die "unlink: $!";

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    First, I used the concatenate . operator (see perlop) instead of addition to create $tempd. Then, I gave mkdir a mode for the new directory. It fails otherwise.

    Things worked fine after that.

    One troubleshooting tip. I always like to print variables (or look at them in a debugger) when things fail suddenly. This should help: print "theLink is set to ->$theLink<-\n";

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Re: unlink unworking
by Maqs (Deacon) on May 17, 2000 at 13:16 UTC
    To avoid errors in creating links and directories you can use readlink function
    i.e. readlink($theLink); to chech if the link exists.
    Then you'd better use time() function to create a uniq name of your directory
    i.e.
    $dirname = $path.time();

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    /Maqs.
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Re: unlink unworking
by btrott (Parson) on May 17, 2000 at 05:53 UTC
    Why don't you change your unlink line to 
        unlink($theLink) or die "unlink of $theLink failed: $!";

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    That'll tell you what it's trying to unlink, at least.
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Re: unlink unworking
by perlmonkey (Hermit) on May 17, 2000 at 12:12 UTC
    I am pretty sure chromatic is correct with the concantenation thing. That and random was not defined for me. 
    #!/usr/bin/perl -w
use strict;
my $tempDir = '/home/pencilneckgeek/tmp/' + rand(10000);
print $tempDir, "\n";

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    Results:
    Argument "/home/pencilneckgeek/tmp/" isn't numeric in add at - line 2.
    2723.31736981869
     Where the big number is supposed to be $tempDir, which is obviously not what you wanted.
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RE: unlink unworking
by turnstep (Parson) on May 17, 2000 at 06:17 UTC

    > $theLink doesn't change at all at
    > any point in the code

    Either it does, or you may have mis-typed the variable name (e.g. $TheLink). The use strict should help ferret the latter out, and btrott's suggestion should show the former.

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