@lineData = split(/\,/, $line); 

should be...

@lineData = split(/\//, $line); #parse 12/Mar/2004

the above results in:
$lineData[0] = 12
$lineData[1] = Mar
$lineData[2] = 2004

This is causing your comparison:

if($lineData[18] == $date) to be wrong

[download]
split divides the string by the character to be split on and returns that many elements to the array. Thus resulting in an array of size 3 for each split per line. 
my $line_date = "$lineData[0]/$lineData[1]/$lineData[2]";
if($line_date eq $date){
  print "equal\n";
}

[download]
Use eq for comparing strings instead of ==

In reply to Re: Parsing a date from comma-delimited file by bear0053
in thread Parsing a date from comma-delimited file by playing18

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