Shell script to become root

Question

How can we write a shell script to become root? That is I donot want to input the password at prompt it should be within the script itself. I was trying to make but failed to do so.Is it possible, if Yes please Explain.

Solution

You can write a script using expect tool.

In Redhat, expect package comes by default. But in Ubuntu you need to install it separately.

You can check this by using commands:

$ rpm -qa | grep expect for Redhat

$ dpkg -l expect for Ubuntu

The following script will do your work:

#!/usr/bin/expect
spawn su -
expect "Password: "
send "password\r"
interact

Comments

[Admin]

Does it need to be a shell script? I don't see how that would be possible, but you could set it up so sudo su or sudo bash works without a password

[Admin]

@MichaelMrozek sudo -i is preferred. It requires permissions to run sudo bash.

[jordanm]

setuid does not work on shell scripts unless you setuid the shell binary (not recommended).