Parse command line : gets « Development « Ruby

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Ruby » Development » gets 




Parse command line


filename = nil
lines = 0               # Default means no truncating

loop do
  begin
    opt, arg = gets
    break if not opt
    case opt
      when "-h"
        puts "Usage: ..."
        break           # Stop processing if -h
      when "-f"
        filename = arg  # Save the file argument
      when "-l"
        if arg != ""
          lines = arg   # Save lines arg (if given)
        else
          lines = 100   # Default for truncating
        end
    end

  rescue => err
    puts err
    break
  end
end

puts "filename = #{filename}"
puts "lines    = #{lines}"

 














Related examples in the same category
1.use gets method to read from standard input (text from your keyboard, by default).
2.Read your name from keyboard
3.Read a line of input into $_
4.Use while loop to read a command
5.The Methods gets and chomp
6.chomp takes off any Enters hanging out at the end of your string
7.Get user's input and process it, ignoring comments and exiting when the user enters the word "quit"
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