ri is a useful documentation tool that ships with the ruby language. To use it
from the command line, type (for example) ri ClassName or ri ClassName.method and ri will
present documentation for the class or method you’ve requested. The docs for
Socket.new, for example:
= Socket.new
(from ruby core)
------------------------------------------------------------------------------
Socket.new(domain, socktype [, protocol]) => socket
------------------------------------------------------------------------------
Creates a new socket object.
domain should be a communications domain such as: :INET, :INET6,
:UNIX, etc.
socktype should be a socket type such as: :STREAM, :DGRAM,
:RAW, etc.
protocol is optional and should be a protocol defined in the
domain. If protocol is not given, 0 is used internally.
Socket.new(:INET, :STREAM) # TCP socket
Socket.new(:INET, :DGRAM) # UDP socket
Socket.new(:UNIX, :STREAM) # UNIX stream socket
Socket.new(:UNIX, :DGRAM) # UNIX datagram socket
The man page for ri is worth a look as it documents a number of handy
different querying techniques that the tool affords for things like limiting
yourself to instance or class methods or partial method name lookup.