get_urls.py

from __future__ import print_function

from glob import glob
from re import findall

urls = set()

for tex in glob('../book/????.tex'):
    for line in open(tex):
        matches = findall(r'\\url\{([^\}]*)', line)
        for match in matches:
            #print match
            urls.add(match)

urls.remove('https://thinkjava.org/')
for url in sorted(urls):
    print(",%s" % url)