I have one pat_array, that has the user given patterns and contains special characters. Let's say "Error 78?" "(Not available) 77%" etc. I need to match the patterns in the 1GB+ log file, after a particular line number till end. I also need to keep a count of which pattern found how many times. This code below works but it takes long, close to 2 mins, for 3 patterns. I was thinking of a way, to avoid the extra for loop while matching the patterns and do it in one shot. (Here for 3 patterns, I match $_ with three different patterns from pat_array, as you can see). I am really really new to perl, so please explain when you help me with the new code/idea. 

my @pat_array = split('@@@', $InListOfPatterns);
my $num_pat = @pat_array;

my @match_count;
for( my $i = 0; $i < $num_pat; $i = $i + 1 ) {
    $match_count[$i] = 0;
}

open LOG_READ,'<',"$InLogFilePath" || die "can not open file :$!";
while (<LOG_READ>) {
    chomp;
    if ( $. > $InStartLineNumber)
    {
      for(my $j = 0; $j < $num_pat; $j = $j + 1 ) {
        if ($_ =~ m/\Q$pat_array[$j]\E/){
        $match_count[$j] = ($match_count[$j] + 1);
        }}}}
close (LOG_READ);

[download]

Thanks in advance. :)

In reply to Multiple patterns match in a big file and track the counts of each pattern matched by ansh007

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