(Perhaps you should re-read Re: When not to use taint mode.)

Insecure dependency in open while running with -T switch at /usr/lib64/perl5/IO/File.pm line 187

That's a hint, but not very helpful. So you managed to pass a tainted value to some IO::File method that calls open. In the current version of IO::FIle (v1.48), line 187 is at the end of the IO::File->open() method.

Luckily, the Carp::Always module can help here. I use a simpler example to demonstrate it:

#!/usr/bin/perl -T
# This is taint.pl

use strict;
use warnings;
use IO::File;

my $fn=$ARGV[0] or die "Missing filename";
my $fh=IO::File->new();
$fh->open($fn,'w') or die "open $fn failed: $!";
$fh->print("This should not happen!");
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Note that you need to start perl with the -T flag if it is also in the #! line:

/tmp>perl -T taint.pl /dev/null
Insecure dependency in open while running with -T switch at /usr/lib64
+/perl5/IO/File.pm line 184.

/tmp>perl -MCarp::Always -T taint.pl /dev/null
Insecure dependency in open while running with -T switch at /usr/lib64
+/perl5/IO/File.pm line 184.
        IO::File::open(IO::File=GLOB(0x1520be8), "/dev/null", "w") cal
+led at taint.pl line 10

/tmp>
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Now, that's more helpful error message. I messed up line 10 of my test script, passing a tainted $fn to IO::File->open(). 'w' can't be tainted, as it is a constant. Why is $fn tainted? Because it was copied from the tainted list of arguments @ARGV. (In theory, $fh could also be tainted, depending on what IO::File->new() does.)

Update: How to debug CGIs from the command line: Re: Running a CGI script from a command line?

Alexander