Learn Ruby the Hard Way: A Simple and Idiomatic Introduction to the Imaginative World of Computational Thinking with Code, Third Edition

Exercise 17. More Files

Now let’s do a few more things with files. We’ll write a Ruby script to copy one file to another. It’ll be very short, but will give you ideas about other things you can do with files.

ex17.rb

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 1    from_file, to_file = ARGV  2  3    puts "Copying from #{from_file} to #{to_file}"  4  5    # we could do these two on one line, how?  6    in_file = open(from_file)  7    indata = in_file.read  8  9    puts "The input file is #{indata.length} bytes long" 10 11    puts "Does the output file exist? #{File.exist?(to_file)}" 12    puts "Ready, hit RETURN to continue, CTRL-C to abort." 13    $stdin.gets 14 15    out_file = open(to_file, 'w') 16    out_file.write(indata) 17 18    puts "Alright, all ...