Need Modifications in my expect script

Question

I have an expect script which performs an SSH to a list of servers with the credentials mentioned in the script. It is not throwing any error when it is unable to SSH to a particular server and continues with the next server in the list. I want the script to let me know when it is unable to SSH with the password given. What changes should be made to the script to get this done?

The first script is a shell script which calls the expect script

#!/usr/bin/ksh
for host_name in `cat list`
do
    /home/user1/ssh_script $host_name
done

#!/usr/local/bin/expect -f
set timeout 1
set host_name [lindex $argv 0]
spawn ssh -q -o StrictHostKeyChecking=no "user1\@$host_name"
expect "*assword:"
send "abcd@123\r";
expect "$\r"
puts "user1 loggedin successfully"
exit
interact

Answer 1

You can match for a timeout "pattern" in the expect lines. For example,

#!/usr/bin/expect -f
proc abort { } { send_user "Timeout!" ; exit 2 }
set timeout 1
set host_name [lindex $argv 0]
spawn ssh -q -o StrictHostKeyChecking=no "user1\@$host_name"
expect timeout abort "assword:"
send "abcd@123\r"
expect timeout abort "assword: " { send_user "bad password\n"; exit 3 } "$\r"
puts "user1 loggedin successfully"

This adds a one line procedure abort to the start, and the pattern+action sequence timeout abort to each expect. This will call the procedure if the expect times out. The procedure writes a string to stdout and exits with return code 2 instead of the default 0. You can test for this exit code in your ksh script if you want to.

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To detect a bad login password, you can look for a second prompt for the password at the same time as looking for the "$" prompt showing you have logged in ok.