Create a shell file with the name of rootpass.sh and add below codes, then give execute permission to that file.

# chmod +x rootpass.sh

Set root password directly in shell script, assume that the root password is: rpasswd



#!/usr/bin/expect -f



spawn sudo -s <<EOF

expect "password:"

send -- "rpasswd\r"

expect eof


If you want to pass arguments(root password)create a file name rootpass.sh and add below code in it.



#!/usr/bin/expect -f



set rpasswd [lindex $argv 0]

spawn su - root

expect  "password:"

send  "$rpasswd\r"

interact


I hope, the above scripts is functional.