Print out entries from the online documentation system. The commands `?' and `information' (usually abbreviated `info') are synonyms for `help'.
The first form prints out a summary table of contents for the entire help system.
The second form prints out the documentation available on the given topic. Many help system entries contain references to other entries accessible in this way. The topic name may be abbreviated; if there is no topic exactly matching the name you give, the help system checks for topics for which the name is a prefix, perhaps with the addition or omission of an initial `@', or perhaps with some confusion beween dashes (-) and underscores (_), e.g., `bui' instead of `building', `who' instead of `@who', `@wri' instead of `write', `add_ent' instead of `@add-entrance', `unlock-' instead of `@unlock_for_open'
If the abbreviation you give is ambiguous, you will be presented with a list of the matching complete topic names.
The `help index' commands prints out a list of indices for the various help databases. Each index gives a list of topics available on that database. It is sometimes easier to find the topics you're interested in this way, rather than tracing through the chain of cross references.