I just wrote a small utility to pull Mac addresses verses port
numbers from our switches and found that the telnet.cmd strings
yielded to the block, were out of synch with the commands. It took me
a while to track it down to the telnet.cmd method of net/telnet.rb
adding a “\n” to the command, The network switch was expecting just a
single key stroke, which is common in text based menu driven
interfaces. The result being that the “\n” caused the switch to
resend to last menu, and I was getting two prompts for command I
sent. Hence the wait method got a command out of synch, for every
command I executed.

I fixed this with a hack to the net/telnet.rb library, which may be
useful to others.
This is the whole rewritten cmd method.

 def cmd(options) # :yield: recvdata
   match    = @options["Prompt"]
   time_out = @options["Timeout"]

   if options.kind_of?(Hash)
     string   = options["String"]
     match    = options["Match"]   if options.has_key?("Match")
     time_out = options["Timeout"] if options.has_key?("Timeout")
     no_nl = options["NoNL"] if options.has_key?("NoNL")

############# >>>>>>>>>>>ADDED THIS LINE
string = options

   ########### >>>>>>>>>>>REPLACED self.puts(string) with this

“if” statement.
if no_nl

   if block_given?
     waitfor({"Prompt" => match, "Timeout" => time_out}){|c|

yield c }
waitfor({“Prompt” => match, “Timeout” => time_out})


Rob B. Ph: +64 (9) 3737 599 Extn 87972
Computing Services Manager Fax: +64 (9) 3737 453
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