jcpunk has asked for the wisdom of the Perl Monks concerning the following question:

In my previous question Expect, STDout, and formating I was having difficulty getting output from expect. thanks to the code snipits provided by my fellow monks I am now able to get output, but alas there is a problem making if make sense. normally i wouldnt post a question that could be titled "why wont if make sense" but alas I am totally stuck.

my problems stem from the inconsistencys of expects loging functionality. ie occassionally /bin/sh will be logged as /\nbin/sh. And to top it off dispite having duplicated every case i can thing would effect my output and compensate for the problems no luck was achieved.
hopefully my code will help explain my question more clearly 

 $exp->log_file(\&formatoutput);
 $exp->send("$CAT /etc/passwd\n");
......
sub formatoutput {
  my $input = shift;
     
  chomp($input);
  $input =~ tr/\r//;
 
  if( ($input ne "$CAT /etc/passwd ") ||
      ($input ne '/bin/sh') ||
      ($input ne "/bin/sh") ||
      ($input ne '\$ ') ||
      ($input ne "\$ ") ||
      ($input ne '/') ||
      ($input ne "/") ||
      ($input ne 'bin/sh') ||
      ($input ne "bin/sh")
    )
   {
     print"${input}\n\n";
   }
}

[download]
the output that I get is 
/

bin/sh

$

root:x:0:1::/:/sbin/sh daemon:x:1:1::/: bin:x:2:2::/usr/bin: sys:x:3:3
+::/: adm:x:4:4:Admin:/var/adm: lp:x:71:8:Line Printer Admin:/usr/spoo
+l/lp: uucp:x:5:5:uucp Admin:/usr/lib/uucp: nuucp:x:9:9:uucp Admin:/va
+r/spool/uucppublic:/usr/lib/uucp/uucico listen:x:37:4:Network Admin:/
+usr/net/nls: nobody:x:60001:60001:Nobody:/: noaccess:x:60002:60002:No
+ Access User:/: nobody4:x:65534:65534:SunOS 4.x Nobody:/: fast:x:204:
+1:FastTrack Server:/web:/bin/sh postfix:x:100:1:postfix:/dev/null:/bi
+n/false vscan:x:1001:10:Amavis User:/usr/local/encap/amavis-perl-11:/
+bin/sh sshd:x:22000:22000:SSHD privsep User:/var/empty:/bin/false

$

[download]
neither of the $'s or the / or bin/sh should be showing up and last run i had the $ and /bin/sh which should also have not shown up, right?

Replies are listed 'Best First'.
Re: inconsisntency, if, expect, logs
by Thelonius (Priest) on Jun 13, 2003 at 18:17 UTC
    Change the || to &&. Your if will always be true with ||. Also, '/bin/sh' and "/bin/sh" are always the same. Read Quote and Quote-like operators in perlop to see when the kind of quote matters.

    Update: Apparently I didn't make myself clear since y'all are still discussing the intricacies of Expect. The simple fact is that the logic in your if statement is wrong. Try this:

    faulty_logic("fred");
faulty_logic("wilma");
faulty_logic("barney");

sub faulty_logic {
  my $input = shift;
  if (($input ne 'fred') ||
      ($input ne 'barney')) {
    print "IF condition true: input=$input\n";
  }
}
__END__

Output:
IF condition true: input=fred
IF condition true: input=wilma
IF condition true: input=barney

    [download]
    Think about it.
[reply]
[d/l]
      You are right about his if, however the if logic being wrong does not explain the newlines being placed in his expect log file. That is what i am after.

      -Waswas
[reply]
Re: inconsisntency, if, expect, logs
by waswas-fng (Curate) on Jun 13, 2003 at 17:30 UTC
    I have not seen this before, and have used expect a lot. Could you post more of your code (the parts that generate the output, and buid $exp) so I can see if it is the way $exp was formed or the commands were run that is causing this. Also a raw dump of the $exp->log_file written to a file with the portion that you show uncorrectly formatted would be helpful.

    -Waswas
[reply]
      here is some more code
      my $exp = new Expect;
....
$exp->raw_pty(1);
$exp->log_stdout(0);
$exp->spawn($telnet $host);||die;
$exp->expect($timeout,
                 ['ogin:', sub { $exp->send("$username\n"); exp_contin
+ue; } ],
                 ['assword:', sub { $exp->send("$password\n"); } ],
                 [timeout => sub { die "<center>ERROR: <BR>A timeout h
+ast occured at login</center>\n"; }  ],
                );
$exp->log_file(\&formatoutput);
$exp->send("/bin/sh\n");

      [download]
      that comprises the rest of my expect usage in this file excluding the soft_close I would be willing to post the whole file, but it is around 600 lines and the rest isnt relavent i think....
[reply]
[d/l]
[select]
        The expect flags look correct, I guess my question is if you just dump the $exp->log_file to a normal file does the file contain an extra \n in the /bin/sh line(s)?

        -Waswas
[reply]

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