This command line fails quietly:

<pre><code>
fossil revert f6eb797b4f 3</i>
revert file '3'? this will destroy local changes y


Of course I really was meant to put a -r in front of the revision number, but the complete absence of any kind of error message (like "file f6eb797b4f not in repository", say) kind of disguised my error.  It may be better if Fossil flags an attempt to revert a file that doesn't exist.