parsing inputs from commandline and creating a latex file from python

gistfile1.py

from optparse import OptionParser

import os
import re
import subprocess
import sys

parser = OptionParser(usage=__doc__.strip())
parser.add_option('-v', dest='verbose', action='store_true',
    help='Verbose output')

header_pat = re.compile(r'^\\PY\{c\}\{' + (r'\\PYZsh\{\}' * 8))

def yield_altered_lines(latex):
    """
    Adds page breaks and page layout to our pygments file. Blah.
    """
    for line in latex.splitlines():
        if line == r'\documentclass{article}':
            yield line
            yield r'\usepackage{geometry}'
            yield r'\geometry{letterpaper,landscape,margin=0.25in}'
        elif line == r'\begin{document}':
            yield line
            yield r'\large'
        elif header_pat.search(line):
            yield r'\end{Verbatim}'
            yield r'\pagebreak'
            yield r'\begin{Verbatim}[commandchars=\\\{\}]'
            yield line
        else:
            yield line

if __name__ == '__main__':
    print
    options, args = parser.parse_args()
    if options.verbose:
        errout = sys.stderr
    else:
        errout = open('/tmp/pep20.log', 'w')

    try:
        # TODO: pygmentize in Python instead of farming it out
        p = subprocess.Popen(
            ('pygmentize', '-f', 'latex', '-l', 'python',
                '-O', 'full', sys.argv[0]),
            stdout=subprocess.PIPE, stderr=errout)
        output, err = p.communicate()
        assert p.returncode == 0, 'pygmentize exited with %d' % p.returncode

        p2 = subprocess.Popen(
            ('pygmentize', '-f', 'html', '-l', 'python',
                '-O', 'full', '-o', 'pep20_by_example.html', sys.argv[0]),
            stdout=errout, stderr=errout)
        p2.communicate()
        assert p2.returncode == 0, 'pygmentize exited with %d' % p2.returncode

    except OSError, e:
        print >> sys.stderr, 'Failed to run pygmentize: %s' % str(e)
    except AssertionError, e:
        print e

    altered_output = '\n'.join(l for l in yield_altered_lines(output))

    try:
        p = subprocess.Popen(('pdflatex',),
            stdin=subprocess.PIPE, stdout=errout, stderr=errout)
        p.communicate(altered_output)
        assert p.returncode == 0, 'pdflatex exited with %d' % p.returncode
    except OSError, e:
        print >> sys.stderr, 'Failed to run pygmentize: %s' % str(e)
    except AssertionError, e:
        print e

    os.rename('texput.pdf', 'pep20_by_example.pdf')

    errout.close()

Taken from http://artifex.org/~hblanks/talks/2011/pep20_by_example.html