There are many built-in routines and data types in Darwin that we
have not yet encountered. Later chapters
contain a more detailed expository of the common but more complex
functions available. Part - The Reference Guide
provides a complete
list of all built-in routines and types
available to the user. Beyond this, there are several fast on-line
ways to look for information regarding built-in tools. The commands
display information about keywords in Darwin which match topic or approximately match topic. (Usage of print results in only exact matches to topic.)
Suppose you would like to know if there is a function available which calculates the square root of a number. To find the appropriate function, one might type
> ? square root;or
> help('square root');
This leads one directly to the function sqrt().
Function sqrt( x:numeric ) Compute the square root of a number.
A list of topics available in the system help is found as follows:
> ? index;Querying the help utility with an item from this list gives more specific information.
A good way to get to know the complement of Darwin tools is to browse through the output produced by the names routine.
> names();This generates a list of all assigned names in your current session. This is especially useful if, during one of your Darwin sessions, you should forget what you have called a variable, data structure or procedure. The forgotten name will appear somewhere in this list. If you accompany the command names with the name of a built-in type, you receive the list of names for routines using that type.