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Subject: Problems with cygwin, "expect" and ssh
Date: Wed, 24 May 2006 09:31:15 -0700
Message-ID: <BD6B3BD6A3C3EC4FBC45FF024CE104370220D037@WAPRDVSEBE10.gsm1900.org>
From: "Stepp, Charles" <Charles DOT Stepp AT T-Mobile DOT com>
To: <cygwin AT cygwin DOT com>
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I have found some interesting behavior regarding the cygwin expect/ssh
problem. I used the little expect script
That Corinna created. It seemed to not see the prompt for the password
from the spawned ssh, so it just timed out. But, when I redirect the
stderr to /dev/null, it behaves correctly. Perhaps ssh is spitting some
spurious bytes to stderr that are causing the expect pattern to not
match:

------------------------------------------------------------------------
GOOD:
cstepp AT FLTAMLP0192593 ~
$ ./sshtest 2>/dev/null
spawn ssh -t 10.65.16.41 
Before expect for assword:
cstepp AT 10 DOT 65 DOT 16 DOT 41's password: Found assword:
Before send of password
After send of password

Last login: Thu Jan 01 1970 00:00:00 from 

[======================================================================]
 Use of this system is explicitly limited to employees...

------------------------------------------------------------------------
-----
BAD:
cstepp AT abcdefghi ~
$ ./sshtest 
spawn ssh -t <hostname> 
Before expect for assword:
cstepp AT 10 DOT 65 DOT 16 DOT 41's password: Spawning failed

cstepp AT abcdefghi ~

------------------------------------------------------------------------
-------
SCRIPT:
cat sshtest
#!/usr/bin/expect -f
set timeout 10

spawn ssh -t <hostname>
puts "Before expect for assword:"
expect {
  "*assword:" {
puts "Found assword:"
        sleep 2
  }
  default {
    send_user "Spawning failed\n"
    exit
  }
}

puts "Before send of password"
send "xxxxxxx\r"
puts "After send of password"
expect {
  -re ".*\\$.* " { }
  default {
    send_user "Sending password failed\n"
    exit
  }
}

send "ls\n"
expect {
  -re ".*\\$.* " { }
  default {
    send_user "Sending ls failed\n"
    exit
  }
}

send "exit\n"
expect {
  -re ".*Connection to mycygwinbox closed.*" { }
  default {
    send_user "Sending exit failed\n"
    exit
  }
}

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