[isabelle-dev] Building nightly snapshots

[Christian Urban]

Dear All,

I am used to building the nightly snapshots, which
in the olden days was conveniently done by the build
script. Well, times change. ;o)

I remember (and again verified just now) that with the 
snapshot from 14 August I can build Isabelle with

  ./bin/isabelle build -v -s -c HOL-Nominal

and then do
  
  ./bin/isabelle install -p ....

to have Isabelle up and running. But doing the same with 
the snapshot from 20 August and also 22 August, I get the 
following error message:


  ./bin/isabelle build -v -s -c HOL-Nominal
  Duplicate session "RAW" (file "/usr/local/src/Isabelle_22-Aug-2012/src/Pure/ROOT")

Any ideas what I do wrong? How can I get the snapshot
to run?

Thanks,
Christian