xkcd download script

#!/usr/bin/python
#Downloads all xkcd comics (as jpgs) and alt-texts

import urllib, os, re
dl_folder = raw_input('Enter destinated folder: ')
if not dl_folder:
  dl_folder = 'xkcd'
  print 'Folder is xkcd by default'
if not os.path.exists(dl_folder):
  print 'Folder does not exists\nFolder created'
  os.mkdir(dl_folder)
else: print 'Folder found'
if not os.path.isfile('alt_text.txt'): alt = file('alt_text.txt','wt')
alt = open('alt_text.txt','r+')
print 'Searching for latest comic'
for line in urllib.urlopen(r'http://www.xkcd.com/').readlines():
  lastcomic = re.search(r'http://xkcd.com/(\d*?)/',line)
  if lastcomic:
    lastcomic = int(lastcomic.group(1))
    print 'Latest comic: '+`lastcomic`
    break
raw_input('You may press CTRL-C to terminate the program at any time\n\nPress ENTER to continue')
try:
  for comic in xrange(1,lastcomic+1):
    for line in urllib.urlopen(r'http://www.xkcd.com/'+`comic`).readlines():
      img = re.search(r'(http://imgs.xkcd.com/comics/.*?(?:png|jpg))">?.*? title="(.*?)"',line)
      if img:
        dl_path = os.path.join(dl_folder,(4-len(`comic`))*'0'+`comic`+'.jpg')
        if not os.path.isfile(dl_path):
          alt.write(`comic`+': '+img.group(2).replace('"','"').replace(''',"'")+'\n')
          urllib.urlretrieve(img.group(1),dl_path)
          print 'Comic '+`comic`+' downloaded'
        else: print 'Comic '+`comic`+' found in folder. Download skipped'
        break
    else: print ('Download of comic '+`comic`+' was unsuccessful','Comic 404 skipped')[comic==404]
except KeyboardInterrupt: print 'Program terminated'
alt.close()