use Time::Local;

    # Array read from log; contains timestamps in any order:
    my @TIMES = <LOG>;

    # Sort array to get the smallest timestamp first and the largest timestamp last:
    sort(@TIMES);

    # re-arrange order to use in timelocal function:
    my ($year1,$mon1,$mday1,$hours1,$min1,$sec1) = ( $TIMES[0]       =~ /(\d+)-(\d+)-(\d+)\s(\d+):(\d+):(\d+).000/ );
    my ($year2,$mon2,$mday2,$hours2,$min2,$sec2) = ( $TIMES[$#TIMES] =~ /(\d+)-(\d+)-(\d+)\s(\d+):(\d+):(\d+).000/ );

    # get timestamp in seconds since beggining of time (in unix world):
    $START_LAUNCH = timelocal($sec1,$min1,$hours1,$mday1,$mon1,$year1);
    $END_LAUNCH   = timelocal($sec2,$min2,$hours2,$mday2,$mon2,$year2);

    # Get difference & Round off to two decimals:
    $TimeInMinutes = sprintf("%.2f",(($END_LAUNCH - $START_LAUNCH)/60)); 

    return $TimeInMinutes;