Simplest Possible Ruby Web Server

Courtesy of Aaron Paterson, here’s a 31-character command line that runs a web server from the current directory on port 5000:

ruby -run -e httpd -- -p 5000 .

Thanks to Benjamin Oakes for bringing this shorter solution to my attention, and for his writeup explaining it.

For posterity, here’s my previous 80-character version (which assumes that you have the Ruby gem thin installed):

ruby -rrack -e "include Rack;Handler::Thin.run Builder.new{run Directory.new''}"

And, drbrain on EFNet IRC suggested:

# Needs sudo since it defaults to port 80
sudo ruby -rwebrick -e 'WEBrick::HTTPServer.new.start'

However this code—while shorter—cannot be simply killed with ctrl-c and thus fails my need to easily start and stop the web server.