Added script to convert newlines between unix mac and windows.

convert_nl.py

@@ -0,0 +1,75 @@
+#!/usr/bin/env python
+
+import os
+import sys
+import re
+from optparse import OptionParser
+
+
+op = OptionParser()
+op.add_option("-u", "--to-unix", dest="u",
+              help="Windows/Mac -> Unix",
+              action='store_true', default=False)
+op.add_option("-m", "--to-mac", dest="m",
+              help="Windows/Unix -> Mac",
+              action='store_true', default=False)
+op.add_option("-w", "--to-windows", dest="w",
+              help="Unix/Mac -> Windows",
+              action='store_true', default=False)
+
+op.usage += """ [<file-or-directory> ...]
+
+Forcefully converts newlines as required.
+Specify individual files or directories to process all files therein.
+
+Each file will be backupped with a .bak extension.
+"""
+
+mac_re = re.compile('\r(?!\n)')
+unix_re = re.compile('(?<!\r)\n')
+win_re = re.compile('\r\n')
+
+transform = {
+# target:
+#    Unix   Mac    Windows
+    (True,  False, False): ((win_re, '\n'), (mac_re, '\n')),
+    (False, True,  False): ((win_re, '\r'), (unix_re, '\r')),
+    (False, False, True): ((unix_re, '\r\n'), (mac_re, '\r\n')),
+}
+
+
+def convert(u, m, w, data):
+    for expr, repl in transform[u, m, w]:
+        data = expr.sub(repl, data)
+    return data
+
+
+def iter_args(args):
+    for arg in args:
+        if os.path.isfile(arg):
+            yield arg
+        elif os.path.isdir(arg):
+            for sub in iter_args(os.path.join(arg, f)
+                                 for f in os.listdir(arg)):
+                yield sub
+
+
+if __name__ == '__main__':
+    opts, args = op.parse_args(sys.argv[1:])
+
+    if (opts.w + opts.u + opts.m) != 1:
+        print "Please specify exactly one of -u, -w, -m."
+        print
+        op.parse_args(["-h"])
+        sys.exit(-1)
+
+    if len(args) == 0:
+        print "Please specify at least one file or directory."
+        print
+        op.parse_args(["-h"])
+        sys.exit(-1)
+
+    for f in iter_args(args):
+        data = open(f).read()
+        open(f + '.bak', 'wb').write(data)
+        open(f, 'wb').write(convert(opts.u, opts.m, opts.w, data))