diff-with tab.diff
--- post image.txt.orig 2010-08-18 20:13:31.616002255 -0500
+++ post image.txt 2010-08-18 20:13:31.616002255 -0500
@@ -1 +1 @@
-preimage
+postimage
--- post image.txt.orig 2010-08-18 20:13:31.616002255 -0500
+++ post image.txt 2010-08-18 20:13:31.616002255 -0500
@@ -1 +1 @@
-preimage
+postimage