Shell Programming and Scripting

#!/usr/bin/expect -f
set timeout 25
set u "souvikm"
set p "pass^123"
set command "oslevel -s"

# Open server_list for read (handle hosts) and config_details for write (handle config)
set hosts [open server_list r]
set config [open config_details w]

# This like turns off local echo -
# for debugging leave it commented and all output will be echoed
#log_user 0

# Loop through each host in the $hosts file

while {[gets $hosts host] >= 0} {
    spawn -noecho ssh -t $u@$host
    expect "?assword:*"
    send -- "$p\r"

    # Wait for original server side prompt
    expect -re "(%|#|>|\$) *$"

    # Change server side prompt to make matching more reliable
    send "PS1='PROMPT# '\r"

    # Wait for new prompt
    expect -re "PROMPT# '(.*)PROMPT# "

    # Execute command
    send "$command\r"

    # Match command output and prompt
    expect -re "\r\n(.*)\r\n(.*)PROMPT# "

    # Load command output into variable output
    set output $expect_out(1,string)

    # Append output into (and host name) to local logfile
    puts $config "$host: $output\r"

    # Send exit to host and wait for connection to close
    send "exit\r"
    expect eof
}
close $hosts
close $config