rackup(1) An utility for run Rack-based applications

Other Alias



rackup [ruby options] [rack options] [rackup config]


Rackup is a useful tool for running Rack applications, which uses the Rack::Builder DSL to configure middleware and build up applications easily.

rackup automatically figures out the environment it is run in, and runs your application as FastCGI, CGI, or standalone with Mongrel or WEBrick -all from the same configuration.


Ruby options:
-e, --eval [LINE]
evaluate a LINE of code
-d, --debug
set debugging flags (set $DEBUG to true)
-w, --warn
turn warnings on for your script
-I, --include [PATH]
specify $LOAD_PATH (may be used more than once)
-r, --require [LIBRARY]
require the library, before executing your script

Rack options:

-s, --server [SERVER]
serve using SERVER (webrick/mongrel)
-o, --host [HOST]
listen on HOST (default:
-p, --port [PORT]
use PORT (default: 9292)
use ENVIRONMENT for defaults (default: development)
-D, --daemonize
run daemonized in the background
-P, --pid [FILE]
file to store PID (default: rack.pid)

Common options:

-h, --help
Show the help message
Show version


This is a simple example on how to start an application based on Rack with rackup:

$ rackup -Ilib blog/config.ru

[2010-12-10 15:01:11] INFO WEBrick 1.3.1

[2010-12-10 15:01:11] INFO ruby 1.9.2 (2010-08-18) [x86_64-linux]

[2010-12-10 15:01:11] INFO WEBrick::HTTPServer#start: pid=4496 port=9292


Copyright (C) 2007, 2008, 2009, 2010 Christian Neukirchen <http://purl.org/net/chneukirchen>

For a complete list of authors and contributors to the project, please take a look here https://github.com/rack/rack/contributors

This manual page was written by Ermenegildo Fiorito [email protected] for the Debian Project