RI(1) Ruby Programmer's Reference Guide RI(1)
NAME
ri — Ruby API reference front end
SYNOPSIS
ri [-ahilTv] [-d DIRNAME] [-f FORMAT] [-w WIDTH] [--[no-]pager]
[--server[=PORT]] [--[no-]list-doc-dirs] [--no-standard-docs]
[--[no-]{system|site|gems|home}] [--[no-]profile] [--dump=CACHE]
[name ...]
DESCRIPTION
ri is a command-line front end for the Ruby API reference. You can
search and read the API reference for classes and methods with ri.
ri is a part of Ruby.
name can be:
Class | Module | Module::Class
Class::method | Class#method | Class.method | method
gem_name: | gem_name:README | gem_name:History
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 ri will search, run:
ri --list-doc-dirs
Specifying the --system, --site, --home, --gems, or --doc-dir options
will limit ri to searching only the specified directories.
ri options may be set in the RI environment variable.
The ri pager can be set with the RI_PAGER environment variable or the
PAGER environment variable.
OPTIONS
-i
--[no-]interactive
In interactive mode you can repeatedly look up methods
with autocomplete.
-a
--[no-]all Show all documentation for a class or module.
-l
--[no-]list List classes ri knows about.
--[no-]pager Send output to a pager, rather than directly to stdout.
-T Synonym for --no-pager.
-w WIDTH
--width=WIDTH Set the width of the output.
--server[=PORT]
Run RDoc server on the given port. The default port
is 8214.
-f FORMAT
--format=FORMAT
Use the selected formatter. The default formatter is bs
for paged output and ansi otherwise. Valid formatters
are: ansi, bs, markdown, rdoc.
-h
--help Show help and exit.
-v
--version Output version information and exit.
Data source options:
--[no-]list-doc-dirs
List the directories from which ri will source documenta-
tion on stdout and exit.
-d DIRNAME
--doc-dir=DIRNAME
List of directories from which to source documentation in
addition to the standard directories. May be repeated.
--no-standard-docs
Do not include documentation from the Ruby standard li-
brary, site_lib, installed gems, or ~/.rdoc. Use with
--doc-dir.
--[no-]system Include documentation from Ruby's standard library. De-
faults to true.
--[no-]site Include documentation from libraries installed in
site_lib. Defaults to true.
--[no-]gems Include documentation from RubyGems. Defaults to true.
--[no-]home Include documentation stored in ~/.rdoc. Defaults to
true.
Debug options:
--[no-]profile
Run with the Ruby profiler.
--dump=CACHE Dump data from an ri cache or data file.
ENVIRONMENT
RI Options to prepend to those specified on the command-line.
RI_PAGER
PAGER Pager program to use for displaying.
HOME
USERPROFILE
HOMEPATH Path to the user's home directory.
FILES
~/.rdoc Path for ri data in the user's home directory.
SEE ALSO
ruby(1), rdoc(1), gem(1)
REPORTING BUGS
• Security vulnerabilities should be reported via an email to
security@ruby-lang.org. Reported problems will be published after
being fixed.
• Other bugs and feature requests can be reported via the Ruby Issue
Tracking System (https://bugs.ruby-lang.org/). Do not report secu-
rity vulnerabilities via this system because it publishes the vul-
nerabilities immediately.
AUTHORS
Written by Dave Thomas <dave@pragmaticprogrammer.com>.
UNIX April 20, 2017 RI(1)
Generated by dwww version 1.16 on Tue Dec 16 07:04:17 CET 2025.