Puts method of interest is part of the IO package
request that documentation by entering ri IO#puts at the command line:
C:\rubydev>ri IO#puts
---------------------------------------------------------------- IO#puts
ios.puts(obj, ...) => nil
------------------------------------------------------------------------
Writes the given objects to _ios_ as with +IO#print+. Writes a
record separator (typically a newline) after any that do not
already end with a newline sequence. If called with an array