From: "Antoine P." <lists@...>
Date: 2012-08-21T20:56:21+09:00
Subject: Strange line feed behavior with ping command.

Hello,

While testing ruby to execute external commands, i'm having a strange
behavior with some commands.

To give an example, I have a simple script which is echoing an external
command result.

I observe different behavior

--- 1st test : DIR command ---

-code- (just a simple echo) :
    IO.popen("dir") do |f|
  while line = f.gets
    puts line;
  end
    end

-result- same as a regular dir executed as a commandline in windows
console :
  D:\test>d:\temp\ruby-1.9\bin\ruby.exe test_dir.rb
   Le volume dans le lecteur D s'appelle DONNEES
   Le numéro de série du volume est C083-B188

   Répertoire de D:\test

  21/08/2012  13:25    <REP>          .
  21/08/2012  13:25    <REP>          ..
  21/08/2012  13:22    <REP>          temp
  21/08/2012  13:24                84 test_dir.rb
  21/08/2012  13:25                95 test_ping.rb
                 2 fichier(s)              179 octets
                 3 Rép(s)  13 118 869 504 octets libres

OK it works !


--- 2nd test : PING command ---

When I try to echo a simple ping localhost with the same script :
-code-
    IO.popen("ping localhost") do |f|
  while line = f.gets
    puts line;
  end
    end

-result- I have a different output with annoying added line feeds which
are not visible in a regular command line :
  D:\test>d:\temp\ruby-1.9\bin\ruby.exe test_ping.rb


  Envoi d'une requête 'ping' sur PC43343 [127.0.0.1] avec 32 octets de
données :



  Réponse de 127.0.0.1 : octets=32 temps<1ms TTL=128

  Réponse de 127.0.0.1 : octets=32 temps<1ms TTL=128

  Réponse de 127.0.0.1 : octets=32 temps<1ms TTL=128

  Réponse de 127.0.0.1 : octets=32 temps<1ms TTL=128



  Statistiques Ping pour 127.0.0.1:

      Paquets : envoyés = 4, reçus = 4, perdus = 0 (perte 0%),

  Durée approximative des boucles en millisecondes :

      Minimum = 0ms, Maximum = 0ms, Moyenne = 0ms


Whereas a regular command line is more compact :
  D:\test>ping localhost

  Envoi d'une requête 'ping' sur PC43343 [127.0.0.1] avec 32 octets de
données :

  Réponse de 127.0.0.1 : octets=32 temps<1ms TTL=128
  Réponse de 127.0.0.1 : octets=32 temps<1ms TTL=128
  Réponse de 127.0.0.1 : octets=32 temps<1ms TTL=128
  Réponse de 127.0.0.1 : octets=32 temps<1ms TTL=128

  Statistiques Ping pour 127.0.0.1:
      Paquets : envoyés = 4, reçus = 4, perdus = 0 (perte 0%),
  Durée approximative des boucles en millisecondes :
      Minimum = 0ms, Maximum = 0ms, Moyenne = 0ms

-analysis- :

I have indeed many successive "\n" linefeeds :
-code-
  output = IO.popen("ping localhost").readlines()
  print output
-result-
  ["\n", "\n", "Envoi d'une requ\x88te 'ping' sur PC43343 [127.0.0.1]
avec 32 oct
  ets de donn\x82es\xFF:\n", "\n", "\n", "\n", "R\x82ponse de
127.0.0.1\xFF: octet
  s=32 temps<1ms TTL=128\n", "\n", "R\x82ponse de 127.0.0.1\xFF:
octets=32 temps<1
  ms TTL=128\n", "\n", "R\x82ponse de 127.0.0.1\xFF: octets=32 temps<1ms
TTL=128\n
  ", "\n", "R\x82ponse de 127.0.0.1\xFF: octets=32 temps<1ms TTL=128\n",
"\n", "\n
  ", "\n", "Statistiques Ping pour 127.0.0.1:\n", "\n", "
Paquets\xFF: envoy\x8
  2s = 4, re\x87us = 4, perdus = 0 (perte 0%),\n", "\n", "Dur\x82e
approximative d
  es boucles en millisecondes :\n", "\n", "    Minimum = 0ms, Maximum =
0ms, Moyen
  ne = 0ms\n", "\n"]


-notes-
  . i have the same behavior if i use puts or print to echo on stdout.
  . i have the same behavior too if i use other apis like popen2 /
popen3 (i tried many things even trying to change encoding mode but with
no success)
  . i'm using ruby 1.9 on window XP profesionnal french


If you have any idea to explain such a behavior and any suggested
solution, i would be grateful.
Note : as i'm evaluating ruby as a scripting tool to write some system
scripts which will manipulate lots of input / output of external
commands, I don't want to manipulate full output or line by line to
delete \n which is not a clean solution in my opinion - so solution MUST
be simple and easy :-) ?

thx by advance

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