Rdoc cheatsheet

# Foo.
#
# @example
#
#   y
#   g
#
# @param [String] param_name The xx and xx.
#
# @see https://example.com/
#
# @return [true] if so

# @param [Hash] opts the options to create a message with.
# @option opts [String] :subject The subject
# @option opts [String] :from ('nobody') From address
# @option opts [String] :to Recipient email
# @option opts [String] :body ('') The email's body

# @param (see User#initialize)
# @param [OptionParser] opts the option parser object
# @param [Array<String>] args the arguments passed from input. This
#   array will be modified.
# @param [Array<String, Symbol>] list the list of strings and symbols.
# @param [Hash<Symbol, String>] a hash with symbol keys and string values
#
# The options parsed out of the commandline.
# Default options are:
#   :format => :dot

# @raise [AccountBalanceError] if the account does not have
#   sufficient funds to perform the transaction

*bold*
_emphasized_
+code+

{ObjectName#method optional title}
{Class::CONSTANT My constant's title}
{#method_inside_current_namespace}

https://www.example.com/
See Models::User@Examples
{Google}[https://google.com/]

def input # :nodoc:

module MyModule # :nodoc: all

# == Definition lists
#
# list::  hi.
# +foo+:: parameterized

# == Definition lists
# [foo]   also
# [bar]   like this

# @return [String]
# @return [String, nil] the name

# :call-seq:
#   ARGF.readlines(sep=$/)     -> array
#   ARGF.readlines(limit)      -> array
#   ARGF.readlines(sep, limit) -> array
#
#   ARGF.to_a(sep=$/)     -> array
#   ARGF.to_a(limit)      -> array
#   ARGF.to_a(sep, limit) -> array

# :category: Utilities

# :section: Expiry methods
# methods relating to expiring

def expire!
def expired?
...

# :markup: TomDoc

Place this at the beginning of the file.