Question

I have the following code:

#!/usr/bin/ruby

require 'socket'

server = '221.186.184.68'

if ( server =~ /^(?:(?:25[0-5]|2[0-4][0-9]|[01]?[0-9][0-9]?)\.){3}(?:25[0-5]|2[0-4][0-9]|[01]?[0-9][0-9]?)$/ )
        hostname = Socket.gethostbyaddr(server.split(".").map(&:to_i).pack("CCCC")).first
        puts hostname
end

All well, but when I input an IP Address that doesn’t reverse I get exeception error:

i.rb:8:in `gethostbyaddr': host not found (SocketError)
        from i.rb:8

How can I hide the message? Thanks!

Answer 1

use exception handling

#!/usr/bin/ruby

require 'socket'

server = '221.186.184.68'

begin
    if ( server =~ /^(?:(?:25[0-5]|2[0-4][0-9]|[01]?[0-9][0-9]?)\.){3}(?:25[0-5]|2[0-4][0-9]|[01]?[0-9][0-9]?)$/ )
        hostname = Socket.gethostbyaddr(server.split(".").map(&:to_i).pack("CCCC")).first
        puts hostname
    end
rescue => err
   #puts "I don't want to print this #{err.message}. Hence commented"
end