is a command-line front end for the Ruby API reference. You can search and read the API reference for classes and methods with

is a part of Ruby.

can be:

All class names may be abbreviated to their minimum unambiguous form. If a name is ambiguous, all valid options will be listed.

A

matches either class or instance methods, while #method matches only instance and ::method matches only class methods.

README and other files may be displayed by prefixing them with the gem name they're contained in. If the gem name is followed by a

all files in the gem will be shown. The file name extension may be omitted where it is unambiguous.

For example:

ri Fil ri File ri File.new ri zip ri rdoc:README

Note that shell quoting or escaping may be required for method names containing punctuation:

ri 'Array.[]' ri compact\!

To see the default directories

will search, run:

ri --list-doc-dirs

Specifying the

or

options will limit

to searching only the specified directories.

options may be set in the

environment variable.

The

pager can be set with the

environment variable or the

environment variable.

In interactive mode you can repeatedly look up methods with autocomplete.

Show all documentation for a class or module.

List classes

knows about.

Send output to a pager, rather than directly to stdout.

Synonym for

Set the width of the output.

Run RDoc server on the given port. The default port is8214.

Use the selected formatter. The default formatter is

for paged output and

otherwise. Valid formatters are:

Show help and exit.

Output version information and exit.

Data source options:

List the directories from which

will source documentation on stdout and exit.

List of directories from which to source documentation in addition to the standard directories. May be repeated.

Do not include documentation from the Ruby standard library,

installed gems, or

Use with

Include documentation from Ruby's standard library. Defaults to true.

Include documentation from libraries installed in

Defaults to true.

Include documentation from RubyGems. Defaults to true.

Include documentation stored in

Defaults to true.

Debug options:

Run with the Ruby profiler.

Dump data from an ri cache or data file.

Options to prepend to those specified on the command-line.

Pager program to use for displaying.

Path to the user's home directory.

Path for ri data in the user's home directory.

Security vulnerabilities should be reported via an email to

Reported problems will be published after being fixed.

Other bugs and feature requests can be reported via the Ruby Issue Tracking System

Do not report security vulnerabilities via this system because it publishes the vulnerabilities immediately.

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