Python version of https://gist.github.com/3773519 that pulls all bookmarks on the first sync, and does incremental updates afterwards. Also uses the Mac OS X keychain to retrieve your password so it doesn't need to live in a file on your computer in plain text.

allpinboard.py

#!/usr/bin/env python

"""
This script is designed to generate a simple html file with _all_ of your
Pinboard.in bookmarks The HTML file can be added to Launchbar's index as a
custom bookmark file and you can search your entire Pinboard.in collection
instantly from Launchbar (by title only). It includes any applied tags as part
of the title to aid in searching.

You should edit the `username`, `bookmark_filename`, and `local_timezone`
variables to suit your preferences.

Requirements:

* pytz
* requests
* dateutil
"""

from datetime import datetime
import subprocess
import os
import cgi

import pytz
import requests
from dateutil import parser as date_parser

# Settings

# Your Pinboard username
username = ""

# The path where you'd like to store your HTML export
bookmark_filename = "/Users/dan/Dropbox/PinboardBookmarks.html"

# Your timezone
local_timezone = "America/Los_Angeles"

# (optional) A tag that you want to export by
tag = None

# Your password
password = ""

# Alternatively (if on OS X), use the Mac OS X keychain
# keychain_process = subprocess.Popen(["security", "find-internet-password", "-s", "pinboard.in", "-w"],
#        stdout=subprocess.PIPE)
# trim_newlines = subprocess.Popen(["tr", "-d", "'\n'"],
#        stdin=keychain_process.stdout,
#        stdout=subprocess.PIPE)
# keychain_process.stdout.close()
# password, _ = trim_newlines.communicate()

url = None
bookmark_format = u"""<a href="{href}" title="{extended}">{description}</a>\n"""
basic_auth = (username, password)

def quote(text):
    return cgi.escape(text, quote=True).replace("\n", " ")

try:
    timestamp = os.stat(bookmark_filename).st_mtime
except OSError:
    if tag:    
        url = "https://api.pinboard.in/v1/posts/all?format=json&tag={}".format(tag)
    else:
        url = "https://api.pinboard.in/v1/posts/all?format=json"
else:
    last_modified_local_time = datetime.fromtimestamp(timestamp, \
            pytz.timezone(local_timezone))
    last_modified = last_modified_local_time.astimezone(pytz.timezone("UTC"))

    # Check if bookmarks have been updated remotely since last local update
    response = requests.get("https://api.pinboard.in/v1/posts/update?format=json",
            auth=basic_auth)
    last_modified_on_server = date_parser.parse(response.json()['update_time'])

    if last_modified_on_server > last_modified:
        if tag:
            url = "https://api.pinboard.in/v1/posts/all?format=json&fromdt={}&tag={}" \
                    .format(last_modified.strftime("%FT%TZ"), tag)
        else:
            url = "https://api.pinboard.in/v1/posts/all?format=json&fromdt={}" \
                    .format(last_modified.strftime("%FT%TZ"))
finally:
    if url is not None:
        response = requests.get(url, auth=basic_auth)
        with open(bookmark_filename, 'a+') as bookmark_file:
            for bookmark in response.json():
                bookmark['description'] = quote(bookmark['description'])
                bookmark['extended'] = quote(bookmark['extended'])
                bookmark_file.write(bookmark_format.format(**bookmark).encode("utf-8"))