Changing linux user name

How To Change or Rename Username and User ID In Linux?

The problem is we want to change the already created user name or user id. As we know there is a lot of configuration those rely on the user id like permissions. We will use usermod command to make this change. Keep in mind this changes will effects system wide.

List User Info

Before starting to big changes we will list users detailed info with cat command like below.

List User Info

• test is our user name for this operation
• 1000 is the current id of our test user.

Change User Name

We will change username with the following command by providing new username. We will provide the -l option with the new username and old username. In this example we will change username ismail into ali .

• usermod is command we issue to chage
• -l ali is the new username
• ismail is the original username

Change User ID

Another opportunity is changing the user ID. Previously we have listed user information of the ismail . We know that the user id of the ismail is 1000 . We will use -u option and the new user id with the user name. In this example we will change the user id of ismail into 1010

• usermod is command used too
• -u 1010 is new user id provided for the user
• ismail is the user whose id will be changed.

Check It Again

After these steps we need to the if there is a problem or everything is OK. We will list user information again with the cat command like below.

• test2 is new username but home directory stays the same
• 1010 is the users new id

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Linux Change or Rename User Name and UID

Linux Change or Rename User Command Syntax

Tutorial details
Difficulty level	Easy
Root privileges	Yes
Requirements	Linux terminal
Est. reading time	5 mintues

The syntax is as follows to rename by user name:
usermod -l login-name old-name

• We use the usermod command in Linux to rename user account. The name of the user will be changed from the old-name to login_name. Nothing else is changed. In particular, the user’s home directory name should probably be changed to reflect the new login name.

The syntax is as follows to rename by a UID (user ID):
usermod -u UID username
Where,

• The numerical value of the user’s ID (UID) . This value must be unique unless the -o option is used. The value must be non-negative. Values between 0 and 99 are typically reserved for system accounts. Any files which the user owns and which are located in the directory tree rooted at the user’s home directory will have the file user ID changed automatically. Files outside of the user’s home directory must be altered
  manually.

List all users in Linux system

Type the following cat command:
cat /etc/passwd
One can use the grep command to filter out only user names:
grep -w ‘^username’ /etc/passwd
grep -w ‘^jerry’ /etc/passwd
Another option is to use the cut command:
cut -d: -f1 /etc/passwd
Sample outputs:

How to Change or Rename Username and UID in Linux

Let us see how to rename user login. First, make sure user name is not logged into the server and any other process is not running under the same user name. I also recommend that you backup any data or server files before changing user names.

View current user and group membership for user named tom

First get user identity using the id command:
id tom
Next use the grep command to grab login info about user named tom from the /etc/passwd file
grep ‘^tom:’ /etc/passwd
See group info about user named tom using the groups command:
grep ‘tom’ /etc/group
groups tom
Find home directory permissions for user named tom, run the following ls command:
ls -ld /home/tom/
Finally, see all Linux process owned by user and group named tom using the ps command:
ps aux | grep tom
ps -u tom

Fig.01: Getting info about user named ‘tom’ on a Linux based system

Rename and change username from tom to jerry on Linux

Type the usermod command as follows:
# id tom
# usermod -l jerry tom
## Verify ###
# id tom
# id jerry
# ls -ld /home/tom

A note about running process

You may see an error as follows if tom is logged in and running jobs:

You need to kill all Linux process owned by user named tom and forcefully logged them out of the system:

Rename and change primary groupname from tom to jerry

Type the usermod command as follows:
# id tom
# groupmod -n jerry tom
## Verify it ###
# id tom
# ls -ld /home/tom
Sample outputs:

Fig.02: Sample session renaming user on a Linux based server

How to change user home directory from /home/tom/ to /home/jerry

The syntax is as follows:
# usermod -d /home/jerry -m jerry
# id jerry
# ls -ld /home/jerry
Sample outputs:

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How to change user tom UID from 5001 to 10000

Type the usermod command as follows:
# id tom
# usermod -u 10000 tom
# id tom

Getting help about usermod command

You can pass the —help option to the usermod command. For instance, type the following command at the shell prompt in Linux:
usermod —help

Options	Description
-c OR —comment	COMMENT new value of the GECOS field
-d OR —home	HOME_DIR new home directory for the user account
-e OR —expiredate	EXPIRE_DATE set account expiration date to EXPIRE_DATE
-f OR —inactive	INACTIVE set password inactive after expiration to INACTIVE
-g OR —gid	GROUP force use GROUP as new primary group
-G OR —groups	GROUPS new list of supplementary GROUPS
-a OR —append	append the user to the supplemental GROUPS mentioned by the -G option without removing the user from other groups
-h OR —help	display this help message and exit
-l OR —login	NEW_LOGIN new value of the login name
-L OR —lock	lock the user account
-m OR —move-home	move contents of the home directory to the new location (use only with -d)
-o OR —non-unique	allow using duplicate (non-unique) UID
-p OR —password	PASSWORD use encrypted password for the new password
-R OR —root	CHROOT_DIR directory to chroot into
-P OR —prefix	PREFIX_DIR prefix directory where are located the /etc/* files
-s OR —shell	SHELL new login shell for the user account
-u OR —uid	UID new UID for the user account
-U OR —unlock	unlock the user account
-v OR —add-subuids	FIRST-LAST add range of subordinate uids
-V OR —del-subuids	FIRST-LAST remove range of subordinate uids
-w OR —add-subgids	FIRST-LAST add range of subordinate gids
-W OR —del-subgids	FIRST-LAST remove range of subordinate gids
-Z OR —selinux-user	SEUSER new SELinux user mapping for the user account

Conclusion

In this tutorial, you learned how to change or rename username and UID in Linux using the usermod command. Read man pages of usermod(8) and groupmod(8) commands for more information see this page.

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How to rename Linux users and their home directory

Overview

In this tutorial, you will learn how to a rename a user in CentOS, Debian, Ubuntu and most other Linux distributions. More than that, you will also learn how to rename thier home directory, primary group, and change their UID.

Renaming Users in Linux

Linux provides a tool named usermod specifically for making modifications to user accounts. In this case we are using it to rename a user account, which is done using the -l flag.

For example, to rename a user named student1 to johndoe, you would run the usermod command as follows.

The -l flag will only change the user’s name. All other things attached to the user will remain unaffected, such as home directory. and UID.

Changing a User’s Home Directory in Linux

After renaming a user it may make sense to change their home directory, too. Otherwise, it would cause a lot of confusion trying to explain why johndoe ‘s home directory is /home/student .

To change the user’s home directory we once again use the usermod command. However, this time we need to perform to actions: change the home directory to a new path, and move the contents from the old path into the new path.

We set the new home directory path using the -d or —home flag with the path to the new directory. We must also use the -m flag to copy the contents of the old home directory into the new one.

Renaming a User’s Group

Every user on a Linux system is created with a group of the same name. When we change the name of a user their group name is left untouched. It’s a good idea to also change the user’s primary group name as well.

To change a user’s primary group name we use the groupmod command with the -n flag. We must supply the old name and a new name.

For example, to rename the newly renamed user johndoe ‘s primary group to johndoe from student1 , we would run the following command.

Changing a User’s UID

A little more rare than renaming a user or changing their home directory is changing their UID. A User’s UID is their unique ID on a Linux system. When we assign permissions to file and directories, we use their UID. Processes started by a user are also executed using a user’s UID.

To change a user’s ID we use the usermod command with the -u flag, followed by a new, unique integer.

For example, to set johndoes UID to 5001, we would run the following usermod command.

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How Do I Change My Username in Linux?

• Modify current username
• Add user and then modify its username
• Determine the user account

Prerequisite

You need to have Linux running on the virtual machine configured on your system. When you install Ubuntu, it requires information like username and password. After providing this information, you will be able to access all the applications and have the privilege to use them.

Modify Current Username

Step 1- User Description: To change the current username in Linux, we use the command to know about the current user and directory. “Whoami” is used to display the username, and “pwd” is used to display commands used to outright the execution. The third command, “gnome-session-quit” is used for logging out from the current account in the system.

After the above command, the system will prompt a message to log out or it will automatically quit from the system.

Step 2-Enter in the command shell: When the login page is displayed, type keys Ctrl+alt+f1 then a command prompt will appear. The system will demand a username and password for the login.

Step 3-Set password for root: Modify the password for the root user. After providing login details, we will implement the appended command to set a password for the root user.

After this command, we will type the current password of the user. Then, you can input the new password you want. After retyping, you will see that password is updated successfully.

Step 4:Login as root: Now, the user will log in to the system as root. After applying the password, you will see that name is changed from aqsayasin to root. The root is a temporary name.

Step 5-Change username from Aqsa Yasin to aqsay: We will change the root name with our desired one. Once the name is initialized, the home directory name will be altered. Following the change, the user name on the login screen is changed.

#usermod –l aqsay aqsayasin

# usermod –d /home/aqsay –m aqsay

#chfn –f aqsay aqsay

After login to “aqsay”, go to the terminal and write the three commands we used to execute earlier in this guide to check the description of a user after alteration. By using these commands, you can see that the username is changed successfully.

Add a New User and then Modify the Username

In accordance with modifying the username, one must have a user in Linux. If there is no existence of any user, we will see how the user is created and modified in the command line of Ubuntu. This creation and modification require the following steps:

Step 1-Add user: You will add a user by the following command. “hania123” is the name we want to give to a new user.

After providing the username, you will be asked to enter a new password. After retyping the password, a message prompting a successful update will appear. Password confirmation will allow you for further verifications and knowledge of the description of the user, .i.e. Full name etc. The user doesn’t need to enter all details, and you can skip it by pressing the “enter” key. The system will confirm the given information by pressing “y” to continue.

Step 2-Identification: After completing the description process, we will log out from the system to ensure the user’s presence on the homepage of Ubuntu.

Step 3-Modification: Moving forward, we will modify the root name of the directory with the help of the below-cited command.

After modifying the user, you will now want to see all users created in Ubuntu. For this purpose, we will use the “ls” command

Now, you will see the names of the users. Then you will log out from the system. After logging in, you will notice that the root name that has been changed from “Aqsa Yasin” to“zahra123”

Determine the User Account Currently in Linux

To know the currently logged-in user, we will come to know it by using a couple of commands.

The “Who” command will let you know about the identity of the user i.e., name of the current user is “aqsay”.

The same answer is obtained by applying “whoami” as a comparative to “who”. Moreover, the same answer is obtained by echoing the “$user”.

One letter word “w” is more effective in giving output in a detailed form. It provides the information of the last 5,10 and 15 minutes, mostly including boot time, etc.

TTY shows the terminal type you are using,:0 means the mouse and keyboard connected with. FROM represent the name of the host. IDLE shows the idle time of the user in the system. [email protected] depicts the time, the user was logged in. JCPU and PCPU represent the joint and process CPU timings. Whereas WHAT shows the current process of the user.

To obtain more details about the user, as we have to know who the user is. The below command is the better way to start.

This command gives us user id (uid), groups of them (gid), and shows the group in which the user has become the member.

If you want to obtain the output of only groups, specific less cluttered view of groups can be obtained.

Conclusion

In the article mentioned above, we have described changing usernames using some set of commands in the terminal and on a simple command-line shell.

About the author

Aqsa Yasin

I am a self-motivated information technology professional with a passion for writing. I am a technical writer and love to write for all Linux flavors and Windows.

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