suggestions to split changeset

[Neal Becker]

Mads Kiilerich wrote:

> Neal Becker wrote, On 10/18/2009 05:29 PM:
>> I have a large repo that was imported from non-hg upstream.  I applied
>> all
>> my favorite patches as one initial changeset.  Now I have applied a few
>> more changesets.
>>
>> I want to split that first changeset up into individual functional
>> changesets.
>>
>> Suggestions how to proceed?
> 
I noticed this http://mercurial.selenic.com/wiki/AtticExtension

splitting patches: 
... put bigpatch into .hg/attic
hg unshelve bigpatch
hg shelve -f --interactive patch1
hg shelve --interactive patch2
hg shelve finalpatch

My question: Step 1 says put bigpatch into .hg/attic.  What is the form of 
this patch?  If I haven't any .hg/attic yet, can I just create an empty 
directory?  Then hg export a patch and put it there?