[Openmcl-devel] hemlock save doc interrupt - diff

[peter]

Working on the same sources from two computers, I'll sometimes fail 
to save a file on one, work on that file in another computer, then 
returning to the first try to quit in order to load my code afresh. 
At that point I'll get a dialog offering:
---
This document's file has been changed by another application since 
you opened or saved it.
The changes made by the other application will be lost if you save. 
Save anyway?
[Save]   [Don't Save]
---
What I want at this point is [Cancel], and I can't command-. abort 
out of the state that I am in.  Is there a way to abort this?

As it is, I go to the file system, copy the version that is there, 
using the save dialog clobber the original, then go back to 
recovering the mess I've made.

At that point, I would like a really good lisp aware file comparison 
utility of any variety.  Has anyone suggestions (other than not 
making a mess in the first place)?

(I find unix (terminal) diff rather useless, but that may be because 
I don't know how to configure the call arguments appropriately.)