vmx@einsnull:~/src/couchdb/tutorial$ ERL_FLAGS="-pa '/home/vmx/src/couchdb/tutorial/couchdb/src/couchdb'" erl
Erlang R13B01 (erts-5.7.2) [source] [64-bit] [smp:2:2] [rq:2] [async-threads:0] [kernel-poll:false]

Eshell V5.7.2  (abort with ^G)
1>     OpenFile = fun(Filename) ->
1>         case couch_file:open(Filename, [create, overwrite]) of
1>         {ok, Fd} ->
1>             {ok, Fd};
1>         {error, Reason} ->
1>             io:format("ERROR (~s): Couldn't open file (~s) for tree storage~n",
1>                       [Reason, Filename]),
1>             {error, Reason}
1>         end
1>     end.
#Fun<erl_eval.6.13229925>
2> {ok, Fd} = OpenFile('/tmp/foo.bin').
{ok,<0.36.0>}
3> c('/home/vmx/src/couchdb/tutorial/couchdb/src/couchdb/numidx.erl').
/home/vmx/src/couchdb/tutorial/couchdb/src/couchdb/numidx.erl:131: Warning: variable 'Fd' is unused
{ok,numidx}
4> numidx:add({Fd, nil}, {<<"NewDocId">>, 456}).
{ok,0}
5>  numidx:add({Fd, 0}, {<<"NewDocId2">>, 4556}).
node: {node,456,[<<"NewDocId">>],nil,nil}
{ok,102}
6>  numidx:add({Fd, 102}, {<<"NewDocId2">>, 46}).
node: {node,456,[<<"NewDocId">>],nil,51}
{ok,196}
7> couch_file:pread_term(Fd, 102).
{ok,{node,456,[<<"NewDocId">>],nil,51}}
8> couch_file:pread_term(Fd, 196).
{ok,{node,456,[<<"NewDocId">>],148,51}}
9> couch_file:pread_term(Fd, 51). 
{ok,{node,4556,[<<"NewDocId2">>],nil,nil}}
10> couch_file:pread_term(Fd, 148).
{ok,{node,46,[<<"NewDocId2">>],nil,nil}}