use Perl

#!/usr/bin/perl -Tw

use warnings;
use strict;

local $/ = ""; # paragraph mode

while ( my $para = <> ) {
    next unless $para =~ s/^=head(\d)\s+//;

    my $level = $1;
    chomp $para;

    print " " x (($level-1)*4) if $level > 1;
    print "$para\n";
}

which gives me nice output like:

NAME
VERSION
SYNOPSIS
IMPORTANT LINKS
CONSTRUCTOR AND STARTUP
    new()
    $mech->agent_alias( $alias )
    known_agent_aliases()
PAGE-FETCHING METHODS
    $mech->get( $url )
    $mech->reload()
    $mech->back()
STATUS METHODS
    $mech->success()
    $mech->uri()
    $mech->response() / $mech->res()
    $mech->status()