Accidentally deleted /etc/sudoers file

I get the following error while trying to update my repositories,

avinash@avinash-VirtualBox:~$ sudo apt-get update sudo: unable to stat /etc/sudoers: No such file or directory sudo: no valid sudoers sources found, quitting sudo: unable to initialize policy plugin 

It seems like I had accidentally deleted my /etc/sudoers file./etc/sudoers file was actually belongs to sudo package, so i try to reinstall sudo by pkexec but it won't work.

avinash@avinash-VirtualBox:~$ pkexec apt-get install sudo Reading package lists... Done Building dependency tree Reading state information... Done sudo is already the newest version. 0 upgraded, 0 newly installed, 0 to remove and 301 not upgraded. 1 not fully installed or removed. After this operation, 0 B of additional disk space will be used. Do you want to continue [Y/n]? y Setting up sudo (1.8.6p3-0ubuntu3.1) ... WARNING: /etc/sudoers not present! chown: cannot access ‘/etc/sudoers’: No such file or directory dpkg: error processing sudo (--configure): subprocess installed post-installation script returned error exit status 1 Errors were encountered while processing: sudo E: Sub-process /usr/bin/dpkg returned an error code (1) avinash@avinash-VirtualBox:~$ 

And also I had tried,

avinash@avinash-VirtualBox:~$ pkexec apt-get install --reinstall sudo Reading package lists... Done Building dependency tree Reading state information... Done 0 upgraded, 0 newly installed, 1 reinstalled, 0 to remove and 301 not upgraded. 1 not fully installed or removed. After this operation, 0 B of additional disk space will be used. E: Internal Error, No file name for sudo:amd64 

How can i make sudo command to work again?

5 Answers

After I made a backup for /etc/sudoers file:

sudo mv /etc/sudoers{,.bak} 

I get the same errors like in your case.

If you use

pkexec apt-get install sudo 

will not work because apt-get will see that:

sudo is already the newest version. 

If you use:

pkexec apt-get install --reinstall sudo 

will also not work because /etc/sudoers file is not found to be removed and replaced.

But if you use:

pkexec apt-get purge sudo pkexec apt-get install sudo 

as described in this answer, everything will work like a charm. I can say this because I just test it again.

So, there is no point to lose time and boot your system with a live disk.

Just boot from Ubuntu live disk and copy /etc/sudoers file to the installed Ubuntu partition's /etc directory.

• Boot Ubuntu live dis and click try Ubuntu option on startup.

• Run sudo blkid command to know the installed Ubuntu's partition id.

• Mount the installed Ubuntu's partition on a specific directory like below,

  sudo mkdir /media/foo sudo mount /dev/sdaX /media/foo # /dev/sdaX installed Ubuntu's partition id. 

• Now copy the live disk's sudoers file to the /etc directory of installed Ubuntu's partition.

  sudo cp /etc/sudoers /media/foo/etc 

• Now boot from the hard-disk(Boot your Ubuntu OS).It will work.

Here's the raw content of /etc/sudoers on Ubuntu 13.10 :

# # This file MUST be edited with the 'visudo' command as root. # # Please consider adding local content in /etc/sudoers.d/ instead of # directly modifying this file. # # See the man page for details on how to write a sudoers file. # Defaults env_reset Defaults mail_badpass Defaults secure_path="/usr/local/sbin:/usr/local/bin:/usr/sbin:/usr/bin:/sbin:/bin" # Host alias specification # User alias specification # Cmnd alias specification # User privilege specification root ALL=(ALL:ALL) ALL # Members of the admin group may gain root privileges %admin ALL=(ALL) ALL # Allow members of group sudo to execute any command %sudo ALL=(ALL:ALL) ALL # See sudoers(5) for more information on "#include" directives: #includedir /etc/sudoers.d 

And the permissions :

-r--r----- 1 root root 

To apply those, it's chmod 440 /etc/sudoers and chown root:root /etc/sudoers

execute pkexec nano /etc/sudoers

and paste

# # This file MUST be edited with the 'visudo' command as root. # # Please consider adding local content in /etc/sudoers.d/ instead of # directly modifying this file. # # See the man page for details on how to write a sudoers file. # Defaults env_reset Defaults mail_badpass Defaults secure_path="/usr/local/sbin:/usr/local/bin:/usr/sbin:/usr/bin:/sbin:/bin" # Host alias specification # User alias specification # Cmnd alias specification # User privilege specification root ALL=(ALL:ALL) ALL # Members of the admin group may gain root privileges %admin ALL=(ALL) ALL # Allow members of group sudo to execute any command %sudo ALL=(ALL:ALL) ALL # See sudoers(5) for more information on "#include" directives: #includedir /etc/sudoers.d 

I just wanted to add this simple solution to reinstall sudo If you removed sudo with:

sudo apt-get remove sudo 

You can install it again. Use:

su - 

Enter your root password and then:

apt-get update apt-get install sudo 

exit