View source for Ruby I/O

== Parsing a File ==
To extract the contents of a file as a single string: 
<source lang="ruby">
lines = open('test.txt').read
</source>

To extract the contents of a file as an array of lines: 
<source lang="ruby">
lines = open('test.txt').readlines
</source>

To process a file line-by-line: 
<source lang="ruby">
open('test.txt').each do |line|
    do something with line
end
</source>


== Write to a file ==

<source lang="ruby">
output = open('output.txt', 'w')
output.puts("Here is the first line")
output.puts("and here is the second line")
</source>


== List a directory ==
<source lang="ruby">
list_of_files = Dir.foreach('/some/directory/path')
</source>


== File Attributes ==
<source lang="ruby">
File.exists?('/some/directory/path')
File.size('/some/directory/path')
</source>

more here:
http://www.ruby-doc.org/core/classes/File.html