EvilZone

I'm guessing you want to check if the urls from urls.txt are working.

Also this code doesn't allow for checking things like 500's, the whole class of 400 error codes, etc. You'd be better off checking against a regex of [2|3][0-9]{2} to catch everything from 200 to 399 all of which are successful links. Also, why no support for https?

Dafaq?

About the code...

+1 for using requests.

    except requests.exceptions.ConnectionError as e:
        print("error exception...")
        pass
There is no reason for a pass statement here. It would've passed anyway.

f = open('urls.txt','r')
a = open('checked.txt','w')
You are right about not being able to close variable 'a' since you need to write to it. 'f' can be closed straightaway however.

for line in f:
  if not line.startswith('http'):
      print line
      a.write(line)
  else::/

if not regex.match(str(r.status_code)):
            a.write(line)A big WTF here. r.status_code is an integer. Why convert it to a string to check if it is between 400 or 599.

I came up with this:
#!/usr/bin/python
import re, requests

f = open('urls.txt','r').readlines()
a = open('checked.txt','w')

misformed_uris = [z.strip() for z in f if not z.startswith('http')]
good_uris = [z.strip() for z in f if z.strip() not in misformed_uris]

[a.write('misformed: %s\n' % z) for z in misformed_uris]

headers = {'User-Agent': 'Bla','Referer': 'http://www.google.com'}

for uri in good_uris:
    try:
        res = requests.head(uri, timeout=4,
                                 headers=headers,
                                 allow_redirects=True,
                                 verify=False)

        a.write('ok: %s\n' % res.url) if res.status_code == 200 \
            else a.write('ok: %s\n' % res.url)

    except requests.exceptions.ConnectionError as e:
        a.write('err: %s\n' % uri)

Works fine. If your urls.txt is this
oidnh
http://cnn.com
egmewpogh
http://blsdgiosdgh.com
wpoe3
http://evilzone.org

checked.txt will be this:
misformed: oidnh
misformed: egmewpogh
misformed: wpoe3
ok: http://edition.cnn.com/
err: http://blsdgiosdgh.com
ok: https://evilzone.org/


One thing I can add to daxda's post is try to work in classes. Look up OOP programming with python. Make multiple .py files so the source code becomes more clear and modular at the same time.