it is finished.

ptd.pl

#!/usr/bin/perl -w
use strict;

sub error {
    my ($error) = @_;
    print $error;
    print "ptd - a todo list utility.\n";
    print "usage:\n";
    print " ptd <action> [options]\n";
    print "actions:\n";
    print "-l                list all entries\n";
    print "-a [entry]        add [entry] as a todo item\n";
    print "-t [number]       toggle an item's todo/done status\n";
    print "-r                remove all completed tasks from the list\n";
    print "-r [number]       remove a specific task from the list\n";
    exit;
}
sub addEntry {
    my ($entry) = @_;
    open(TODO, '>>./.ptd');
    print TODO "todo: $entry \n";
    print "added '$entry' to todo list.\n";
    exit;
}

sub countItems {
    my ($target) = @_;
    open(TODO, './.ptd') or die 'please create a .ptd file';
    @_ = ();
    for $_ (<TODO>) { push @_, $1 if /^$target:(.*)$/; }
    close TODO;

    return @_;
}

sub printTodo {
    my @todo = countItems('todo'); my @done = countItems('done');
    my $x = 1;
    print "todo:\n";
    for my $todo (@todo) { print "$x:$todo\n"; $x++; }
    print "done:\n";
    for my $done (@done) { print "$x:$done\n"; $x++; }
    exit;
}

sub toggleItem {
    my ($num) = @_; my @items = ('');
    open(TODO, './.ptd'); my @lines = <TODO>; close TODO;
    for my $_ (@lines) { if (/^todo:/) { push @items, $_; } }
    for my $_ (@lines) { if (/^done:/) { push @items, $_; } }

    open(TODO, '>./.ptd');
    for $_ (@lines) {
	if (/$items[$num]/) { s/(todo|done)/$1 eq 'todo' ? 'done' : 'todo'/e; }
	print TODO;
    }
    close TODO;
    print "toggled status of $items[$num]";
    exit;
}

sub removeItems {
    open(TODO, './.ptd'); my @lines = <TODO>; close TODO;
    my @newlines; my $removed = 0;
    for my $_ (@lines) {
	unless (/^done/) {push @newlines, $_; };
	if (/^done/) { $removed++; };
    }
    open(TODO, '>./.ptd'); for $_ (@newlines) { print TODO; }; close TODO;
    print "removed $removed completed items\n";
    exit;
}

sub removeItem {
    my ($num) = @_; my @items = ('');
    open(TODO, './.ptd'); my @lines = <TODO>; close TODO;
    for my $_ (@lines) { if (/^todo:/) { push @items, $_; } }
    for my $_ (@lines) { if (/^done:/) { push @items, $_; } }

    open(TODO, '>./.ptd');
    for my $_ (@lines) { unless (/$items[$num]/) { print TODO; } } close TODO;

    print "removed $items[$num]";
}
       
my $args = $#ARGV;
$_ = $ARGV[0];

if ($args == -1) { error("please specify at least one arguement\n\n"); }
if ($args == 0) {
    if (/-l/) { printTodo; }
    if (/-r/) { removeItems; }
    else { error("i don't understand what you're saying\n\n"); }
}
if ($args == 1) {
    if (/-a/) { addEntry($ARGV[1]); }
    if (/-t/) { toggleItem($ARGV[1]); }
    if (/-r/) { removeItem($ARGV[1]); }
}