Creating users in Ubuntu can be done with one of two commands:
useradd. This can be a little confusing at first, because both of these commands do the same thing (in different ways) and are named very similarly. I’ll go over the
useradd command first and then I’ll explain how
adduser differs. You may even prefer the latter, but we’ll get to that in a moment.
Using useradd Command
First, here’s an example of the
useradd command in action:
With this command, I created a user named
jdoe. With the
-d option, I’m clarifying that I would like a home directory created for this user, and following that, I called out
/home/jdoe as the user’s home directory. The
-m flag tells the system that I would like the home directory to be created during the process; otherwise, I would’ve had to create the directory myself. Finally, I called out the username for my new user (in this case,
Now, list the storage of
/home using the following command:
You should see a folder listed there for our new user.
What about creating our user’s password? We may have been asked for our current user’s password due to using
sudo, but we weren’t asked for a password for the new user. To create a password for the user, we can use the
passwd command defaults to allowing you to change the password for the user you’re currently logged in as, but it also allows you to set a password for any other user if you run it as
root or with
sudo. If you enter
passwd by itself, the command will first ask you for your current password, then your new password, and then it will ask you to confirm your new password again. If you prefix the command with
sudo and then specify a different user account, you can set the password for any user you wish.
Using adduser Command
In the preceding process, I executed
sudo adduser dscully (commands that modify users require
root) and then I was asked a series of questions regarding how I wanted the user to be created. I was asked for the password (twice),
Work Phone, and
Home Phone. In the
Other field, I entered the comment
Trust no one, which is a great mindset to adopt while managing users. The latter prompts prior to the final confirmation were all optional: I didn’t have to enter
Room Number, and so on. I could’ve pressed to skip those prompts if I wanted to. The only thing that’s really required is the username and the password.
From the output, we can see that the
adduser command performed quite a bit of work for us. The command defaulted to using
/home/dscully as the home directory for the user, the account was given the next available User ID (UID) and Group ID (GID) of
1002, and it also copied files from
/etc/skel into our new user’s
home directory. In fact, both the
useradd commands copy files from
adduser is more verbose regarding the actions it performs.
adduser command is much more convenient in the sense that it prompts you for various options while it creates the user without requiring that you memorize command-line options. It also gives you detailed information about what it has done. At this point, you may be wondering why someone would want to use
useradd at all, considering how much more convenient
adduser seems to be. Unfortunately,
adduser is not available on all distributions of Linux. It’s best to familiarize yourself with
useradd in case you find yourself on a Linux system that’s not Ubuntu.
It may be interesting for you to see what exactly the
adduser command is. It’s not even a binary program—it’s a shell script. A shell script is simply a text file that can be executed as a program. In the case of
adduser, it’s a script written in Perl, which is a programming language that is sometimes used for administrative tasks. Since it’s not binary, you can even open it in a text editor in order to view all the code that it executes behind the scenes. However, make sure you don’t open the file in a text editor with
root privileges, to ensure that you don’t accidentally save changes to the file and break the script. The following command will open
adduser in a text editor on an Ubuntu Server system:
Now that we know how to create users, it will be useful to understand how to remove them as well.
Removing/Deleting users from Ubuntu
Removing access is very important when a user no longer needs to access a system, as unmanaged accounts often become a security risk. To remove a user account, we’ll use the
Before removing an account, though, there is one very important question you should ask yourself. Will you still need access to the user’s files? Most companies have retention policies in place that detail what should happen to a user’s data when he or she leaves the organization. Sometimes, these files are copied into an archive for long-term storage. Often, a manager, coworker, or a new hire will need access to the former user’s files, perhaps to continue working on a project where they left off. It’s important to understand this policy ahead of managing users. If you don’t have a policy in place that outlines retention requirements for files when users resign, you should probably work with your management and create one.
By default, the
userdel command does not remove the contents of the user’s
home directory. Here, we use the following command to remove
dscully from the system:
We can see that the files for the
dscully user still exist by entering the following command:
The home directory for the user dscully still exists, even though we removed the user.
/home directory for
dscully still existing, we’re able to move the contents of this directory anywhere we would like to. If we had a directory called
/store/file_archive, for example, we could easily move the files there:
Of course, it’s up to you to create the directory where your long-term storage will ultimately be, but you get the idea.
If you weren’t already aware, you can create a new directory with the
mkdir command. You can create a directory within any other directory that your logged-in user has access to. The following command will create the
file_archive directory I mentioned in the preceding example:
-p flag simply creates the parent directory if it didn’t already exist.
If you do actually want to remove a user’s home directory at the same time that you remove an account, just add the
-r option. This will eliminate the user and their data in one shot:
To remove the
/home directory for the user after the account was already removed (if you didn’t use the
-r parameter the first time), use the
rm -r command to get rid of it, as you would any other directory:
It probably goes without saying, but the
rm command can be extremely dangerous. If you’re logged in as
root or using
sudo while using
rm, you can easily destroy your entire installed system if you’re not careful. DO NOT run this command, but as a hypothetical example, the following command (while seemingly innocent at first glance) will likely completely destroy your entire filesystem:
I accidentally typed a space after the first forward slash. I literally accidentally told my system to remove the contents of the entire filesystem. If that command was executed, the server probably wouldn’t even boot the next time we attempted to start it. All user and program data would be wiped out. If there was ever any single reason for us to be protective over the
root account, the
rm command is certainly it!
At this point, we understand how to add and remove users.