tests/md5sum.py

Tune a bit the extdiff toplevel comments/samples.

* Capitalize the first letter of all sentences

* Add an example for GNU diff(1) 'context diff' mode.

* Explain the requirement for separate cmd.xxx and opts.xxx
  options in .hgrc, which hopefully will guard against users
  trying to add:

      [extdiff]
      # Add a new Mercurial command called `cdiff', which calls
      # GNU diff(1) in 'context diff' mode.
      cmd.cdiff = diff -Nprc5

  which fails for recent crew builds with:

      $ hg cdiff .
      making snapshot of 1 files from rev 07dc4a569f4e
      making snapshot of 1 files from working dir
      diff -Nprc5: not found

  The correct way to do this is by separating the cmd.cdiff and
  opts.cdiff parts like this:

      [extdiff]
      # Add a new Mercurial command called `cdiff', which calls
      # GNU diff(1) in 'context diff' mode.
      cmd.cdiff = diff
      opts.cdiff = -Nprc5

  so add it as a new example and explicitly describe it in the
  extdiff comments.

#! /usr/bin/env python
#
# Based on python's Tools/scripts/md5sum.py
#
# This software may be used and distributed according to the terms
# of the PYTHON SOFTWARE FOUNDATION LICENSE VERSION 2, which is
# GPL-compatible.

import sys
import os
import md5

for filename in sys.argv[1:]:
    try:
        fp = open(filename, 'rb')
    except IOError, msg:
        sys.stderr.write('%s: Can\'t open: %s\n' % (filename, msg))
        sys.exit(1)
    
    m = md5.new()
    try:
        while 1:
            data = fp.read(8192)
            if not data:
                break
            m.update(data)
    except IOError, msg:
        sys.stderr.write('%s: I/O error: %s\n' % (filename, msg))
        sys.exit(1)
    sys.stdout.write('%s  %s\n' % (m.hexdigest(), filename))

sys.exit(0)