This works for me under WIN32 and linux, perl 5.6.0. 

C:\>type test.pl
#!/usr/bin/perl

use strict;
use warnings;
use diagnostics;

open  (OUTPUTFILE, ">./file.txt") || die "Oops $!";
my $tmp_dir = "foo";
my $dir = "bar";

if ($tmp_dir ne $dir) {
    print OUTPUTFILE "\n" . $tmp_dir . "\n";
    $dir = $tmp_dir;
}

close OUTPUTFILE;

C:\>perl test.pl

C:\>type file.txt

foo

C:\>

The only way I could reproduce the error you describe is to
do this (ie put in a != in place of ne):

C:\>type test.pl
#!/usr/bin/perl

use strict;
use warnings;
use diagnostics;

open  (OUTPUTFILE, ">./file.txt") || die "Oops $!";
my $tmp_dir = "foo";
my $dir = "bar";

if ($tmp_dir != $dir) {
    print OUTPUTFILE "\n" . $tmp_dir . "\n";
    $dir = $tmp_dir;
}

close OUTPUTFILE;

C:\>perl test.pl
Argument "foo" isn't numeric in numeric ne (!=) at test.pl line 11 (#1
+)

    (W numeric) The indicated string was fed as an argument to an oper
+ator that
    expected a numeric value instead.  If you're fortunate the message
    will identify which operator was so unfortunate.


C:\>

If you genuinely have ne I suspect your perl may be broken!!

If you have ne in the above code perl is quite happy even
if both the vars *are actually numeric* vis:

C:\>type test.pl
#!/usr/bin/perl

use strict;
use warnings;
use diagnostics;

open  (OUTPUTFILE, ">./file.txt") || die "Oops $!";
my $tmp_dir = 2;
my $dir = 1;

if ($tmp_dir ne $dir) {
    print OUTPUTFILE "\n" . $tmp_dir . "\n";
    $dir = $tmp_dir;
}

close OUTPUTFILE;

C:\>perl test.pl

C:\>

Note that this runs quite happily. Perl stringifies the 
numeric values in $tmp_dir and $dir for ne to use.

Because the behavior you describe is not repeatable, and should
not logically occur as perl should be automatically stringifying
the values in $tmp_dir and $dir if required I suggest you may have
a corrupt perl binary. It does happen.


I agree that use strict; use warnings; and use diagnostics;
may help. Unfortunately if you have a big script that was not 
written under use strict you will have a lot of tweaking to do 
yo get it to run (mostly declaring your variables with my), 
but other stuff too.

Good luck

Suggest testing on another box to test dud perl hypothesis


tachyon
[download]