Tag Archives: sudo


how to create a sudo user in Ubuntu

If you’ve installed Ubuntu 11.10 (or older version such as 11.04 or any other similar linux distributions such as Linux Mint 12) – then during installing process, you created a super user by default, but sometimes you need to create another user with root power i.e you want to create a sudo user, right? Yeah! because it’s not a good idea to use (or enable, because it’s disabled by default) root account for administrative tasks.

Creating another user or simply the user management in Ubuntu is not a complex task – as you can easily create/delete/update users from a clean, simple and easy to use graphical interface (Go to Top Right -> Click on Your Name -> Then click on your Icon). That’s it. No, there is another way to do that – from terminal – using some funky terminal commands.


The above snapshot, explains the process of creating a new user account in Ubuntu 11.10 (running Gnome 3 with Gnome Shell Interface, wondering what theme? it’s Zukito; Isn’t it cool :)). Everything seems to be self explanatory. So lets move on to terminal approach which is more funky, powerful and preferred among linux users.

Create a User

To create a user in Ubuntu, open terminal (Ctrl+Alt+t) and execute the command (replace user_name with the username of your choice etc coolgeek).

sudo adduser user_name

(Then you will be prompted to Enter the details for the new user such as password, Name, Room Number, Phone Number etc, just enter the details correctly and hit ‘y’)

Granting sudo power to the User

Now, you’ve created the user, you can add the user to sudo group (which is created by default in Ubuntu, you could also use admin group) using the following command –

sudo adduser user_name sudo


sudo adduser user_name admin


In the case if sudo group doesn’t exist or you want to create your own group then use the following commands –

Creating a Group (User Group)

First create a group using the command (Replace group_name with the group you want to create e.g geeky)-

sudo addgroup group_name

Then add that group to sudoers file, to do that first open the file using the command –

sudo visudo

and  add the following line to the bottom of the file (then save the file and exit).

%group_name  ALL=(ALL:ALL) ALL

Although creating groups isn’t necessary but it makes user management (with different privileges) much easier. Anyway, if you just want to grant root permission to any user then add this line to the sudoers file –

user_name  ALL=(ALL:ALL) ALL

That’s All. Enjoy 🙂

What is sudo in Ubuntu?

Sudo commands in linuxIn early days it was difficult to manage the permissions for different users in a multiuser operating system that may be a client or server;suppose every user has a power of a superuser or root then any one of them may be misused the system either intentionally(If the user is smart) or ignorantly(If the user is a beginner one).Hence the simple solution of this problem is to limit the power for every users according to their need so that they can do simple tasks normally but in case of any administrative task root power is granted for small period(usually five minutes)by using the sudo commands.In sudo su stands for superuser and do means do(as usual).Hence sudo is mostly used by a permitted user for taking the permission to execute some commands as a another user or superuser, according to the information specified in sudoers file.Suppose the user that is invoking a command using the sudo power, is root then there is no need to enter user password.By default authentication is required and the user password is required; the user may use the sudo power again for short period of time(5-15min).So sudo is very useful in finishing some administrative task by a simple user.Now we are going to learn something more about the sudo commands.

Syntax of the sudo commands :

It is very simple..just use the word sudo before the actual command and hit enter.Then it will ask for the users password ..enter the password after the authorization process the commands will execute.e.g I am trying to execute commands1(installing a package using apt-get).

user840@user840-desktop:~$ sudo commands1
[sudo] password for user840:
Reading package lists… Done
Building dependency tree
Reading state information… Done

….and so on the execution will complete.

Options in SUDO :

-A : Using this option the another helper program(It may be in graphical format) is called and executed to read the password of the user and output the user password to the canonical output.

-u user : this option tells the sudo to run the target command as a user instead of root(which is default case).You may use UID rather than username by using UID followed by ‘#’.i.e #uid.
-a : It is used by the sudo to use the special authentication type for the validation of the user according to the permission settings stored in /etc/login.conf.
This option is is used only in the system having the support with BSD authentication mechanism.

-b : Specifying -b(background) with the sudo command simply means to order the sudo that “run the target command in background”.

-p prompt : By using -p (prompt) one can easily customize the password prompt.So using some ‘%’ escapes(e.g %H,%h,%p) you may use any other prompt rather then the default one.

Although there are many other options available but you can easily find out in your bash shell.just type info sudo and hit enter.

Environment Variables :

here are the some environment variables used by the sudo.

USER : Set to the current user.By default its value is equal to root if -u option is not specified.

SUDO_UID : user ID of the user who used the sudo.

SUDO_USER : Set to the login of the permitted user who is using sudo.
Go to your bash terminal for the details about the more environmental variables(info sudo OR man -k sudo OR help sudo).

Credit : Todd C. Miller