Check out example codes for "A Ruby write to file example". It will help you in understanding the concepts better.
Code Example 1
# open and write to a file with ruby
open('myfile.out', 'w') do |f|
f.puts "Hello, world."
end
# an alternative approach:
open('myfile.out', 'w') do |f|
f << "Hello, world.\n"
end
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