perl increasing the counter number every time the script running - perl

Question

I have a script to compare 2 files and print out the matching lines on the file. what I want to add a logic to help me to identify for how long these devices are matched. currently I have add the starting point 1 so I want to increase that number every time the script run and matched.
Example.
inputfile:-########################
retiredDevice.txt
Alpha
Beta
Gamma
Delta
prodDevice.txt
first
second
third
forth
Gamma
Delta
output file :-#######################
final_result.txt
1 Delta
1 Gamma
my objective is to add a counter stamp on each matching line to identify for how long "Delta" and "Gamma" matched. the script running every week. so every time the script running adding 1 so when I audit the 'finalResult.txt. the result should looks like
Delta 4
Gamma 3
the result indicate me Delta matched for last 4 weeks and Gamma for last 3 weeks.
#! /usr/local/bin/perl
my $ndays = 1;
my $f1 = "/opt/retiredDevice.txt ";
my $f2 = "prodDevice.txt";
my $outfile = "/opt/final_result.txt";
my %results = ();
open FILE1, "$f1" or die "Could not open file: $! \n";
while(my $line = <FILE1>){ $results{$line}=1;
}
close(FILE1);
open FILE2, "$f2" or die "Could not open file: $! \n";
while(my $line =<FILE2>) {
$results{$line}++;
}
close(FILE2);
open (OUTFILE, ">$outfile") or die "Cannot open $outfile for writing \n";
foreach my $line (keys %results) {
my $x = $ndays;
$x++;
print OUTFILE "$x : ", $line if $results{$line} != 1;
}
close OUTFILE;
Thanks in advance for any help!

Answer 1

Based on your earlier question and comments, perhaps this might work.
use strict;
use warnings;
use autodie;
my $logfile = 'int.txt';
my $f1 = shift || "/opt/test.txt";
my $f2 = shift || "/opt/test1.txt";
my %results;
open my $file1, '<', $f1;
while (my $line = <$file1>) {
chomp $line;
$results{$line} = 1;
}
open my $file2, '<', $f2;
while (my $line = <$file2>) {
chomp $line;
$results{$line}++;
}
{ ############ added part
my %c;
for (keys %results) {
$c{$_} = $results{$_} if $results{$_} > 1;
}
%results = %c;
} ############ end added part
my (%log, $log);
if ( -e $logfile ) {
open $log, '<', $logfile;
while (<$log>) {
my ($num, $key) = split;
$log{$key} = $num;
}
}
open $log, '>', $logfile or die $!;
for my $key (keys %results) {
my $old = ( $log{$key} || 0 ); # keep old count, or 0 otherwise
my $new = ( $results{$key} ? 1 : 0 ); # 1 if it exists, 0 otherwise
print $log $old + $new, " $key\n";
}

Answer 2

Perform this computation in two steps.
Each time you run the comparison between retired and prod, produce an output file that you save with a unique file name, e.g. result-XXX where XXX denotes when you ran the comparison.
Then write a script which iterates over all of the result-XXX files and produces a summary.
I would name the files result-YYYY-MM-DD where YYYY-MM-DD is the date that the comparison was created. Then it will be relatively easy to iterate over a subset of the files (e.g. ones for a certain month).
Or store the data in a relational database.