Shell Programming and Scripting

cat server_list  
server1 
server2 
server3 
.. 
.. 
..

cat for_loop.sh  
for i in `cat server_list` 
do 
multibos -S 
done

cat expect_script.sh  

spawn /$HOME/for_loop.sh  
expect "*User_ID*" 
send "souvikm\r" 
expect "*Password*" 
send "passw0rd\r" 
expect eof

$> ./expect_script.sh

#!/usr/bin/expect -f
#
#

# set credentials - NOT RECOMMENDED METHOD
set u "username"
set p "password"

# get host name from command-line
set h [lindex $argv 0]

# set the command to run
set cmd "date"

# spawn a connection to the host and
# run the given command
spawn ssh -t $u@$h $cmd

# handle the password prompt
expect "?assword:*"
send -- "$p\r"
send -- "\r"

# done
expect eof

I've found reading files using Expect to be a bit flaky, so you could use a while loop to parse your file with the hostnames and feed it to the Expect script like so:

while read hosts;do sendCmd $hosts;done < server_list

Output:

spawn ssh -t username@server1 date
username's Password:
Mon Nov 11 08:52:42 EST 2013
Connection to server1 closed.

#!/usr/bin/expect -f
#
#

# set credentials
set u "msouvik"
set p "pass^123"

# get host name from command-line
# set h "my_desired_server"

# set the command to run
set cmd "echo Hello Souvik!  >> /export/home/msouvik/echo.out"

# spawn a connection to the host and run the given command
spawn -noecho ssh -t $u@$h $cmd

# handle the password prompt
expect "?assword:*"
send -- "$p\r"
send -- "\r"

# done
expect eof

for h in `cat my_server_list`
do
<Path of above written expect script>
done

#!/usr/bin/expect -f
#
#
for h in `cat my_server_list`
do

# set credentials
set u "msouvik"
set p "pass^123"

# get host name from command-line
# set h ""

# set the command to run
set cmd "echo Hello Souvik!  >> /export/home/msouvik/echo.out"

# spawn a connection to the host and run the given command
spawn -noecho ssh -t $u@$h $cmd

# handle the password prompt
expect "?assword:*"
send -- "$p\r"
send -- "\r"

# done
expect eof

done

set h [lindex $argv 0]

while read hosts;do sendCmd $hosts;done < my_server_list

or 

while read hosts
do
    sendCmd $hosts
done < my_server_list

#!/usr/bin/expect -f
set timeout 2
set u "souvikm"
set p "passw0rd"
set command "multibos -S"

set hosts [open server_list r]
set config [open config_details w]

#log_user 0

while {[gets $hosts host] >= 0} {
    spawn -noecho telnet $host
    expect "*User_ID*"
    send -- "$u\r"
    expect "?assword*"
    send -- "$p\r"
    send "PS1='PROMPT# '\r"
    expect -re "PROMPT# '(.*)PROMPT# "
    send "$command\r"
    expect -re "\r\n(.*)\r\n(.*)PROMPT# "
    set output $expect_out(1,string)
    puts $config "$host: $output\r"
    send "exit\r"
    expect eof
}
close $hosts
close $config

#!/usr/bin/expect -f
#
#

# set credentials
set u "msouvik"
set p "pass^123"

# get host name from command-line
set h [lindex $argv 0]

# set the command to run
set cmd "echo Hello Souvik!  >> /export/home/msouvik/echo.out.$h"

# spawn a connection to the host and run the given command
spawn -noecho ssh -t $u@$h $cmd

# handle the password prompt
expect "?assword:*"
send -- "$p\r"
send -- "\r"

# scp the data onto NIM server
spawn -noecho scp $u@$h:/export/home/msouvik/echo.out .

# done
expect eof

while read h
> do
> expect_script.sh $h
> done < lsnim

cat expect_script.sh
#!/usr/bin/expect -f
#
#

# set credentials
set u "msouvik"
set p "pass^123"

# get host name from command-line
set h [lindex $argv 0]

# set the command to run
set cmd "echo Hello Buddy! >> /export/home/msouvik/echo.out"

# spawn a connection to the host and run the given command
spawn -noecho ssh -t $u@$h $cmd

# handle the password prompt for ssh
expect "Password:*"
send -- "$p\r"
send -- "\r"

# scp the data onto NIM server
spawn -noecho scp $u@$h:/export/home/msouvik/echo.out /export/home/msouvik/echo.out.$h

# handle the password prompt for scp
expect "Password:*"
send -- "$p\r"
send -- "\r"

# done
expect eof