#!/usr/bin/perl
use warnings;
$file =...
open (TEMP, $file) or die("Error: cannot open $file\n");
$outfile =...
open (OUTPUT,">$outfile");
select(OUTPUT);   # explicitly select the new file for output
#declare variables
$counter_A=0;              
$counter_B=0;              #counter for time of the day
$counter_C=2;              #counter for day of the week,date starts on tuesday
@interval = (1..35040);    #15 mins interval over a year 365 days
$nline = "\n";
$scomma = ", ";
$i = 0;

while ($line = <TEMP>)
{   
    @column = split (/,/,$line);
    @speed = split (/_/,$column[5]);
        foreach $timeint (@interval)
          { 
             if ($counter_A==4)
                { $counter_A = 0;
                  $counter_B++;
                     if ($counter_B==24)
                        {$counter_B = 0;
                         $counter_C++;
                         $i = 0;
                             if (($counter_C>=6) && ($counter_C<8))
                                  {
                                    $i = 96;
                                  }
                             if ($counter_C==8)
                                  {  
                                     $counter_C = 1;
                                     
                                   }
                        }
                }
print OUTPUT trim($column[0]).$scomma.trim($column[1]).$scomma.$speed[$i].$nline
$counter_A++;
$i++;
         }
 }