Interpret a unified diff

Interpret-unified-diff.py

import sys, os, difflib, argparse

from datetime import datetime, timezone

def file_mtime(path):

t = datetime.fromtimestamp(os.stat(path).st_mtime,

timezone.utc)

return t.astimezone().isoformat()

def main():

parser = argparse.ArgumentParser()

parser.add_argument('-c', action='store_true', default=False,

help='Produce a context format diff (default)')

parser.add_argument('-u', action='store_true', default=False,

help='Produce a unified format diff')

parser.add_argument('-m', action='store_true', default=False,

help='Produce HTML side by side diff '

'(can use -c and -l in conjunction)')

parser.add_argument('-n', action='store_true', default=False,

help='Produce a ndiff format diff')

parser.add_argument('-l', '--lines', type=int, default=3,

help='Set number of context lines (default 3)')

parser.add_argument('fromfile')

parser.add_argument('tofile')

options = parser.parse_args()

n = options.lines

fromfile = options.fromfile

tofile = options.tofile

fromdate = file_mtime(fromfile)

todate = file_mtime(tofile)

with open(fromfile) as ff:

fromlines = ff.readlines()

with open(tofile) as tf:

tolines = tf.readlines()

if options.u:

diff = difflib.unified_diff(fromlines, tolines, fromfile, tofile, fromdate, todate, n=n)

elif options.n:

diff = difflib.ndiff(fromlines, tolines)

elif options.m:

diff = difflib.HtmlDiff().make_file(fromlines,tolines,fromfile,tofile,context=options.c,numlines=n)

else:

diff = difflib.context_diff(fromlines, tolines, fromfile, tofile, fromdate, todate, n=n)

sys.stdout.writelines(diff)

if __name__ == '__main__':

main()