I want to automate
sudo su - user
from a script. It should then ask for a password.
I will try and guess what you asked.
If you want to use
sudo su - user without a password, you should (if you have the privileges) do the following on you sudoers file:
<youuser> ALL = NOPASSWD: /bin/su - <otheruser>
<yourusername>is you username :D (saumun89, i.e.)
<otheruser>is the user you want to change to
Then put into the script:
sudo /bin/su - <otheruser>
Doing just this, won't get subsequent commands get run by
<otheruser>, it will spawn a new shell. If you want to run another command from within the script as this other user, you should use something like:
sudo -u <otheruser> <command>
And in sudoers file:
<yourusername> ALL = (<otheruser>) NOPASSWD: <command>
Obviously, a more generic line like:
<yourusername> ALL = (ALL) NOPASSWD: ALL
Will get things done, but would grant the permission to do anything as anyone.
You can use command
echo "your_password" | sudo -S [rest of your parameters for sudo]
(Of course without [ and ])
Please note that you should protect your script from read access from unauthorized users. If you want to read password from separate file, you can use
sudo -S [rest of your parameters for sudo] < /etc/sudo_password_file
(Or whatever is the name of password file, containing password and single line break.)
From sudo man page:
-S The -S (stdin) option causes sudo to read the password from the standard input instead of the terminal device. The password must be followed by a newline character.
The easiest way is to make it so that user doesn't have to type a password at all.
You can do that by running
visudo, then changing the line that looks like:
someuser ALL=(ALL) ALL
someuser ALL=(ALL) NOPASSWD: ALL
However if it's just for one script, it would be more secure to restrict passwordless access to only that script, and remove the
(ALL), so they can only run it as root, not any user , e.g.
Cmnd_Alias THESCRIPT = /usr/local/bin/scriptname someuser ALL=NOPASSWD: THESCRIPT
man 5 sudoers to see all the details in the sudoers man page.