Bitcoin charity donation methodology

import os

## Consumes a text file organized like this:
# http://address1.com
# [address1.com's Bitcoin address]
# http://anotheraddress.org
# [anotheraddress.org's Bitcoin address]
# http://somerandomcharity.net
# [somerandomcharity's Bitcoin address]
## Outputs:
# http://address1.com [address1.com's Bitcoin address] 123.456789
# http://anotheraddress.org [anotheraddress.org's Bitcoin address] 85.10245
# http://somerandomcharity.net [somerandomcharity's Bitcoin address] 542.9808
## Assumes:
# A file "prc" contains data in the form "2010-09-06 31.91", describing Bitcoin prices for all dates.
lines = open('addresslist','r').readlines()
prc = {x[:x.find(' ')] : float(x[x.find(' ')+1:].replace('\n','')) for x in open('prc','r').readlines()}

o = {}

lastname = ''

for l in lines:

  if l[:4] == 'http': lastname = l.replace('\n','')
  else:
    os.popen('wget -O ff http://blockexplorer.com/address/' + l)
    datalines = os.popen("cat ff | tr '\\n' ' ' | sed 's_</tr>_</tr>\\n_g' | grep Sent | sed 's_</td>_\\t_g' | awk -F '\\t' '{print $2 $3}'| grep -o '(201.*' | awk '{print $1 $3}' | sed 's/^(//g' | sed 's/<td>/ /g'").readlines()
    data = [[x[:x.find(' ')], float(x[x.find(' ')+1:].replace('\n',''))] for x in datalines]
    tot = sum([x[1] * prc[x[0]] for x in data])
    rec = float(os.popen("cat ff | grep -o '<li>Received BTC:[^/]*</li>' | grep -o '[0-9\.]*'").read().replace('\n',''))
    sent = float(os.popen("cat ff | grep -o '<li>Sent BTC:[^/]*</li>' | grep -o '[0-9\.]*'").read().replace('\n',''))
    final = tot + (rec-sent) * prc['2012-12-22']
    o[lastname] = final
    print '%s \t %s \t %f' % (lastname, l.replace('\n',''), final)