[uwiger]

In practice, one will have to refrain from some of the crazier stuff when working interactively in the shell of a production system. However, it's extremely useful for debugging and minor adjustments by a skilled engineer. Things you can do include inspection of data structures, (very) careful tracing, loading of instrumented modules or minor corrections.

Since Erlang is dynamically typed, practically all data structures can be inspected at run-time, and one particularly nice thing about the Erlang shell is that it tends to be responsive even when the system is operating at near-maximum load.