CODEWITHSUNDEEP
linuxbashshellkshexpect
Eytan
Eytan

Reputation: 171

expect script + fit expect in case password not needed

The following expect script work fine when $IP of Linux machine ask password after login

But on some cases some Linux machines not need password for ssh ( we can login without password) ,

so I need to change my expect script in order to support machines without password

Please advice how to fit my expect script in order to support machines with password and machines without password

 * target of the following expect script is to check the hostname on remote Linux machine


 expect_test=`cat << EOF
 set timeout -1
 spawn  ssh $IP  hostname
       expect {
                 ")?"   { send "yes\r"  ; exp_continue  }
                 word:  {send "pass123\r"     }
      }
 expect eof
 EOF`



 expect -c "$expect_test"

example of exe on remote machine (with password)(name of remote machine - Linux1_machine )

  IP=10.17.18.6

  expect -c "$expect_test"

  spawn ssh 10.17.18.6 hostname
  sh: /usr/local/bin/stty: not found
  This computer system, including all related equipment, networks and network devices     (specifically including Internet access),is pros
  yes
  Password: 
  Linux1_machine

example when we exe the expect script on machine that not need password for login 

 IP=10.10.92.26


 expect -c "$expect_test"


 spawn ssh 10.10.92.26 hostname
 sh: /usr/local/bin/stty: not found
 Linux15_machine
 expect: spawn id exp5 not open
 while executing
 "expect eof"

Upvotes: 1

Views: 2974

Answers (1)

dunxd
dunxd

Reputation: 958

You have a couple of options.

If you know what to expect from the servers you don't have to login to (e.g. session goes straight to the prompt) then add an expect statement with that:

expect {
                     ")?"   { send "yes\r"  ; exp_continue  }
                     word:  {send "pass123\r"     }
                     "prompt"    { do something }
          }

In case you don't have consistent prompts, you could try using a Regular Expression detecting a wide range of prompts:

set prompt “(%|#|\\$) $” ;# default prompt
expect {
      ")?"   { send "yes\r"  ; exp_continue  }
      word:  {send "pass123\r"     }
      -re $prompt { do something }
}

If you don't know what you will get at all (seems unlikely) then you can also add an action when Expect times out.

expect {
                 ")?"   { send "yes\r"  ; exp_continue  }
                 word:  {send "pass123\r"     }
                 timeout { do something }
      }

that will allow expect to move when it doesn't receive the other expected lines.

See http://wiki.tcl.tk/11583 for specific examples of what you are trying to do. Also, the Getting Started with Expect chapter from the Oreilly book is worth a read.

Upvotes: 2

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