
Rules for prints generated by penguin:

There are six kinds of prints:
   1. the output assembly
   2. updates on progress for interactive examination
   3. timings
   4. deterministic dumps
   5. nondeterministic/solver-influenced dumps
   6. random other debug messages

Category (1) goes to the output file, set with -o.

Category (2) always goes to stdout. This is expected to be the
terminal, for the benefit of the person attending the run, if any.
These messages are generated by default. For batch jobs where nobody
is there to see, like overnight test runs, use -q to silence. Using
-v (verbose) will add extra prints. These are mostly useful for
debugging.

Category (3) is sent to stdout by default. To save to a file, use -t.

Category (4) is enabled with -d (dumps). The output goes to a dump
file named in parallel with the output file. This material can be
expected to be stable across multiple runs. It is never printed to
stdout, on the grounds that there's too much of it to be useful there.

Category (5) is enabled with -d (dumps) and -v (verbose) and goes to
the same dump file.

Category (6) is ... hopefully nonexistent.
