$ ./pants cache --read-from=['blah'] test examples/tests/scala/::
INFO] Detected git repository at /Users/stuhood/src/pants on branch master

10:24:50 00:00 [main]
               (To run a reporting server: ./pants server)
10:24:50 00:00   [bootstrap]
10:24:50 00:00   [setup]
10:24:50 00:00     [parse]
               Unknown goal(s): cache

10:24:51 00:01   [complete]
               FAILURE