Take the 2-minute tour ×
Super User is a question and answer site for computer enthusiasts and power users. It's 100% free, no registration required.

I want to automate

sudo su - user 

from a script. It should then ask for a password.

share|improve this question
1  
Don't sudo su - user, use sudo -iu user instead. (Easier to manage through sudoers, by the way.) –  grawity Feb 9 '11 at 12:07
    
How are you able to run sudo su without being able to run sudo visudo? –  Hello71 Feb 10 '11 at 1:33

3 Answers 3

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>

where:

  • <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.

share|improve this answer
    
when the sudo su - user command gets executed,it asks for a password. i want a solution in which script automaticaaly reads password from somewhere. i dont have permission to do what u told earlier. –  sam Feb 9 '11 at 11:43
    
i have the permission to store password in a file. the script should read password from that file –  sam Feb 9 '11 at 11:47

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

to

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

Run man 5 sudoers to see all the details in the sudoers man page.

share|improve this answer
    
i do not have permission to edit sudoers file.. any other so that it should read password from somewhere so that automation of this can be done. –  sam Feb 9 '11 at 11:34
    
you are out of luck ... you could do this with, lets say expect but that would let the password for your user hardcoded somewhere, where people could see it (granted that you setup permissions the right way, it could still be read by root). –  Torian Feb 9 '11 at 11:40
    
Try using expect. man expect for details. –  Mikel Feb 9 '11 at 11:40
    
when the sudo su - user command gets executed,it asks for a password. i want a solution in which script automaticaaly reads password from somewhere. i dont have permission to edit sudoers file.i have the permission to store password in a file.the script should read password from that file –  sam Feb 9 '11 at 11:46

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.
share|improve this answer

Your Answer

 
discard

By posting your answer, you agree to the privacy policy and terms of service.

Not the answer you're looking for? Browse other questions tagged or ask your own question.