Add the specific sed statement to recover the second output file to
the comments.
diff --git a/Tools/scripts/ndiff.py b/Tools/scripts/ndiff.py
index 2ba5e53..4767d1f 100755
--- a/Tools/scripts/ndiff.py
+++ b/Tools/scripts/ndiff.py
@@ -6,7 +6,6 @@
# ndiff file1 file2 -- a human-friendly file differencer.
# $Revision$
-# $NoKeywords: $
# SequenceMatcher tries to compute a "human-friendly diff" between
# two sequences (chiefly picturing a file as a sequence of lines,
@@ -52,6 +51,12 @@
# 3) Lines beginning with "? " attempt to guide the eye to intraline
# differences, and were not present in either input file.
#
+# COROLLARY:
+# On Unix, the second file can be recovered by piping the output through
+# sed -n '/^[+ ] /s/^..//p'
+# Modifications to recover the first file are left as an exercise for
+# the reader.
+#
# NOTE on junk: the module-level names
# IS_LINE_JUNK
# IS_CHARACTER_JUNK