How can I implement SPAWN command with while loop to provide 'password' multiple times?

I'm trying to write a script where based on a given list of hostnames from input.txt file, I have to copy a file from the source server to the destination server for the user - alex.
Password is same for all hosts.

this asks for password every time and I tried SPAWN command with expect and send.

The below scripts give password automatically, only for the first prompt.

I'm aware there are other ways like SSH keys and password-less authentication.

But my exact requriement here is when I trigger the script - copying.sh it will ask multiple times for the "password", in this example 3 times as there are 3 different hosts and I should be able to send it from spawn_file.exp.

Can some one help me how can I implement it and what changes should I make ?

# copying.sh
#------------------------
while read line 
do
    scp /usr/file.txt  alex@${line}://home/temp/
done < input.txt 


#Spawn_file.exp
#------------------------
set timeout -1
spawn sh copying.sh
match_max 100000
expect -exact "Password: "
send -- "abcd1234"
expect eof


#input.txt
#------------------------ 
hostname1
hostname2
hostname3

Solution

THis is where you use the exp_continue command:

#Spawn_file.exp
#------------------------
set timeout -1
spawn sh copying.sh
match_max 100000
expect {
    -exact "Password: " {
        send -- "abcd1234"
        exp_continue
    }
    eof
}

That expect statemennt will wait for either "password" or eof.

If the password prompt is seen, the password will be send, and we'll "loop" in the expect statement
If eof is seen, there is no action, the expect statement ends, and then the expect script ends.