Nil parameter in OptionParser

Question

i try to set my script to run something like this

ruby Script.rb --ip "192.168.3.206"

But if there is no ip parameter then it use default "192.168.1.1

I try this code, but it's always return nil as ip

options = {}

OptionParser.new do |opts|
  options[:ip] = "192.168.1.1"
  opts.on("-i", "--ip", String, "Set ip") do |command_line_ip|
    options[:ip] = command_line_ip
  end
end.parse!
p options

Output of this code is

{:ip=>nil}

Please, tell me where is my code wrong?

moritz · Accepted Answer · 2012-02-23 10:21:25Z

4

You have to indicate that there is an argument to your --ip switch like this:

opts.on("-i MANDATORY", "--ip=MANDATORY", String, "Set ip") do |command_line_ip|

answered Feb 23, 2012 at 10:21

moritz

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1 Comment

nflauria Over a year ago

Just to clarify. It does not have to be the string 'MANDATORY', it can be any string you'd like, it simply denotes that the command accepts a value afterwards. For example: opts.on('--width NUM', Integer, 'Set width of game board') do |w|

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