Markdown Watcher and auto regenerater

gistfile1.py

#!/usr/bin/env python
'''
Markdown Watcher and auto regenerater

While sitting in an aeroplane, I found myself editing a bunch of Markdown
files and needing to regenerate the HTML and preview in a browser.
It was tedious re-typing the 'markdown' command every time, so I made 
this little script to watch the *.markdown files and create the corresponding
.html flavour if the modification date of the markdown file is newer or the
html does not exist yet.

No idea if this already existed, to grab it in stead of making it. 
I could not search, having no connectivity. (of course it does exist, this is a common usecase)
And besides, sometimes just writing the code is quicker than trying to find exactly what you need by Googling.

NOTE: This assumes you have the 'markdown' executable installed on your path.
'''

import os, time, sys

while True:
    f = [x for x in os.listdir('.') if x.lower().endswith('.markdown')]
    for x in f:
        base = x.split('.')[0]
        hbase = '%s.html'%base
        gen = False
        if not os.path.exists(hbase):
            gen = True
        else:
            if os.stat(x).st_mtime > os.stat(hbase).st_mtime:
                gen = True
        if gen:
            sys.stderr.write('\rDetected change in %s regenerating %s' % (x, hbase))
            os.system('markdown %s > %s' % (x, hbase))
    for x in range(3):
        time.sleep(1)
        sys.stderr.write('.')
    sys.stderr.write('\r!                                                                      \r')