Shell Programming and Scripting

#!/usr/bin/perl 

use warnings;
use strict;


my (%m, @d, $d, @r, $r);

@m{ qw[ jan feb mar apr may jun jul aug sep oct nov dec ] } = 0 .. 11;

while (<>) {
  
do {
  @d = split/[\s:]/;
  $d = join '', $d[2], $m{$d[1]}, $d[0], $d[3], $d[4];
    } if /^\d{2} \w{3} \d{4} \d{2}:/;
  
do {
  push @r, [$d, $r]; 
  undef $r; 
  next;
    } if /^---/;      

$r .= $_;     

}

  
print map {
  $/ . $_->[1] . ("-") x 50 . $/ 
  } sort { 
    $a->[0] <=> $b->[0] 
    } @r;

<script_name> input_file

perl -ne'BEGIN {
  @m{
    qw[ jan feb mar apr maj jun jul aug sep oct nov dec ]
    } = 0 .. 11;
  } 
  do {
    @d = split/[\s:]/;
    $d = join "", $d[2], $m{$d[1]}, $d[0], $d[3], $d[4];
    } if /^\d{2} \w{3} \d{4} \d{2}:/;
  do {
    push @r, [$d, $r]; 
    undef $r; 
    next;
    } if /^---/;      
  $r .= $_;     
  END {
    print map {
      $_->[1] . ("-") x 50 . $/ 
      } sort { 
        $a->[0] <=> $b->[0] 
        } @r;
   }' output.txt > output_sorted.txt