Sometimes, you need to change or modify the details of an existing user in the system. At that time, you can use the usermod command to modify those details. Here, In this article, I will describe all the features and uses of the usermod command in Linux with multiple examples.
A. Description
The usermod command is a useful tool to modify the attributes of an existing user. This command allows the root user or superuser to modify the user name, user ID, groups, home directory, password, user shell, expiry date, and other user details of an existing user. Generally, the usermod command provides the opportunity to modify the file like /etc/group, /etc/shadow, /etc/gshadow, /etc/login.def & /etc/passwd.
Note: You must be logged in as the root user or you must use the “sudo” command to execute the “usermod” command with root privileges.
B. Syntax
The syntax of the usermod command in Linux is pretty simple, as shown below.
usermod [OPTION]... USERNote: In the syntax above, the OPTION enclosed by the square bracket means it is not mandatory and three dots after the square bracket mean multiple OPTIONS can be used after the usermod command.
C. Options
There are numerous options available for the usermod command. In the section below, I have listed a few of them. You can learn more about the usermod command, its options and their uses by checking the man page.
man usermodUseful Options
- -a, –append: Use toadd the user to the one or more supplementary group. You can Use it only with the -G
- -b, –badnames: Permit non-compliant names.
- -c, –comment:Use to add comment field for the user account.
- -d, –home:Use to modify the login directory for any existing user account.
- -e, –expiredate:Use to set account expiry date. The date is specified in the format YYYY-MM-DD.
- -f, –inactive:The number of days after a password expires until the account is permanently disabled.
- -g, –gid:Change the primary group for a User.
- -G, –groups:Use To add supplementary groups.
- -l, –login:To change the login name from user_name to new_user_name.
- -L, –lock:To lock the user’s password.
- -m, –move-home:moving the contents of the home directory from the existing home directory to the new directory.
- -o, –non-unique:This option allows to change the user ID to a non-unique value.
- -p, –password: Allows to specify new un-encrypted password.
- -R, –root CHROOT_DIR: Apply changes in the CHROOT_DIR directory and use the configuration files from the CHROOT_DIR directory.
- -s, –shell:Specify the user’s new login shell.
- -u, –uid: Specify the new numerical value of the user’s ID.
- -U, –unlock:Unlock a user’s password.
Note: Commands and their options are case-sensitive in Linux. So, be careful while using them.
Practical Examples of the “usermod” Command in Linux
In Linux, the usermod command is a helpful tool that allows superuser or root user to modify the user name, user ID, groups, home directory, password, user shell, expiry date, and other user details of an existing user. In the section below, I will show you some of the most useful applications for the usermod command in Linux.
Example 1: Rename the User With the “usermod” Command in Linux
The usermod command in Linux allows you to modify an existing user name by simply running the usermod command followed by the option -l. Here, I will modify a user name from “mary” having a UID 2031 to “lisa” with the usermod command. You can do the same by following the steps below.
Steps to follow >
➊ At first, open the Ubuntu Terminal.
➋ Run the command below:
id mary➌ Now, press the ENTER key.
You will receive Mary’s UID, GID and a list of the groups she is a member of, as shown in the image below.
➍ Execute the command below to rename.
sudo usermod -l lisa maryAlternatively,
sudo usermod --login lisa mary➎ Type your password.
➏ Tap ENTER again.
➐ Now, type the following command into the command prompt:
id lisa mary➑ Hit ENTER button.
Output >
In the following image, you can see that user mary has been renamed to lisa with the previous UID 2031.
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Example 2: Modify the User UID With the “usermod” Command in Linux
You can modify the UID of any user by running the usermod command with the option –uid or -u. In this case, I’ll modify lisa‘s UID (currently 2031) and assign UID to 2040 using the usermod command. By using the steps listed below, you can achieve the same results.
Steps to follow >
➊ Open the Ubuntu Terminal first.
➋ Type the following command into the command prompt
id lisaIn the following image, you can see the IDs of the user “lisa” including UID which is 2031.
➌ Now execute the command below to alter its UID.
sudo usermod --uid 2040 lisaAlternatively,
sudo usermod -u 2040 lisa➍ Tap the ENTER button.
➎ Type your Password.
➏ Hit ENTER again.
➐ You can check the UID by typing the following command.
id lisa➑ Now, press ENTER key
Output >
You can see in the image below that I have modified the UID of lisa with the UID “2040“.
Example 3: Modify the User UID With a Non-Unique Value
The UID needs to be an individual, non-negative number. However, you can create users with duplicate (non-unique) UIDs by using the -o or –non-unique option. Here, I will replace the UID of “lisa“ with the same UID as “john” using the usermod command. You can do the same by following the steps below.
Steps to Follow >
➊ Launch the Ubuntu Terminal first.
➋ Type the following command into the command prompt:
id lisa john➌ Press the ENTER button.
In the following image, you can see that the users named lisa and john have UID values of 2040 and 2028, respectively.
➍ Now, enter the following command into the command prompt:
sudo usermod -o -u 2028 lisaAlternatively,
sudo usermod --non-unique --uid 2028 lisa➎ Type your Password.
➏ Press ENTER again.
➐ You can check the GID by typing the following command.
id lisa john➑ Press the ENTER key.
Output >
In the image below, you can see that I have changed the UID of lisa with the same UID as john.
Note: As the user with UID 2028 is a member of group john with GID 2028. So, the group of lisa also turned into jhon while I changed the UID.
Example 4: Modify the User GID With the “usermod” Command in Linux
You can modify the GID of any user by running the usermod command with the option –gid or -g. In this case, I’ll modify john‘s GID (currently 2028) and assign GID to 2040 using the usermod command. By using the steps listed below, you can achieve the same results.
Steps to follow >
➊ Open the Ubuntu Terminal first.
➋ Type the following command into the command prompt
id jhonIn the following image, you can see the IDs of john including GID which is 2028.
➌ Now execute the command below to alter its GID.
sudo usermod --gid 2040 johnAlternatively,
sudo usermod -g 2040 john➍ Tap the ENTER button.
➎ Type your Password.
➏ Hit ENTER again.
➐ You can check the UID by typing the following command.
id john➑ Now, press ENTER key
Output >
You can see in the image below that I have modified the GID of john with the GID “2040“.
Example 5: Add a User to Secondary Groups Using “usermod” Command in Linux
The usermod command allows you to add a user to one or more secondary groups. For adding a user to secondary groups you have to use option -G after the usermod command. Now, I will add the user named john to multiple groups named group4(GID 2029), group5(GID 2030) and group6(GID 2031). You will able to do this if you follow the steps below.
Steps to Follow >
➊ Launch the Ubuntu Terminal.
➋ Type the following command into the command prompt:
sudo usermod -G 2029,2030,2031 johnAlternatively,
sudo usermod --groups 2029,2030,2031 john➌ Now, tap the ENTER button.
➍ Type your Password.
➎ Tap ENTER again.
➏ Now type the following command into the command prompt:
id john➐ Press ENTER key.
Output >
You can see in the image below that I have added user john to group4, group5, group6.
Note: A primary group in Linux is the group to which a user belongs initially, and it is used to specify the group ownership of files and directories that the user creates. In addition to their primary group, users can also be a part of other groups, which are referred to as supplementary groups or secondary groups. These groups are used to grant additional permissions or access to resources.
Example 6: Append a User to Secondary Groups Along With the Existing Groups
In the previous example, I have shown you the process to add a user to secondary groups. Now, If I try to add user jhon to other secondary groups only with option -G then the previous secondary groups will disappear. So, to add john to other secondary groups without overwriting others, you have to use option -a or –append along with the option -G or –groups. In this section, I will show the process to add john to a new group named group8(GID 2033) without losing the membership of group4, group5 and group6. You can do the same by following the steps below.
Steps to Follow >
➊ Firstly, open the Ubuntu Terminal.
➋ Execute the following command
sudo usermod -a -G 2033 johnAlternatively,
sudo usermod --append --groups 2033 john➌ Now, tap the ENTER button.
➍ Give your Password.
➎ Press ENTER again.
➏ Now type the following command into the command prompt:
id john➐ Hit ENTER key.
Output >
In the following image, you can see that the user john has become a member of group8 without losing the membership of previous secondary groups.
Example 7: Adding Information to User Account With “usermood” Command in Linux
The usermod command allows you to add information to a user account in the form of a comment. For adding information to a user account option -c or –comment after the usermod command. At this point, I will add a comment to the user named john. You will able to do the same if you follow the steps below.
Steps to Follow >
➊ Launch the Ubuntu Terminal.
➋ Type the following command into the command prompt:
sudo usermod -c "this is john" johnAlternatively,
sudo usermod --comment "this is john" john➌ Now, tap the ENTER button.
➍ Type your Password.
➎ Tap ENTER key again.
➏ Now type the following command into the command prompt:
grep john /etc/passwd➐ Press ENTER key.
Output >
In the following image, you can see that I have added information about the user john in the form of a comment.
Example 8: Change the User Home Directory With the “usermod” Command in Linux
You can use the usermod command in Linux to change the current home directory of a user. To change the current home directory, -d or –home is used after the usermod command. In this example, I will change the home directory of the user james(/home/james) and use the home directory of user david(/home/david) as james’s home directory. You can check the home directory of users david and james by executing the command below.
getent passwd david james
You can also change the home directory of any user by following the steps below.
Steps to Follow >
➊ Open the Ubuntu Terminal.
➋ Execute the following command
sudo usermod -d /home/david jamesAlternatively,
sudo usermod --home /home/david james➌ Now, tap the ENTER button.
➍ Type your Password.
➎ Press ENTER again.
➏ Now type the following command into the command prompt:
getent passwd james➐ Tap ENTER key.
Output >
You can see in the image that the home directory of user james has changed to /home/david from /home/james.
Example 9: Move the Content of the User’s Home Directory Using “usermod” Command in Linux
When you change the home directory of any user, the content of the previous home directory does not shift to the new home directory. So, if you want to shift a user’s home directory along with the content of the home directory, then you have to use the -m or –move-home option after the usermod command. In this example, I will move the home directory of user Lisa, whose current home directory is at /home/Lisa, to the directory /home/amdadul/Public along with the existing content of /home/Lisa. To check the home directory of user Lisa run the command below.
getent passwd LisaThen you can see the terminal as the image shown below.
If you want to move any user’s home directory along with the contents, then follow the steps listed below.
Steps to Follow >
➊ At first, open the Ubuntu Terminal.
➋ Run the command below:
sudo usermod -d /home/amdadul/Public -m LisaAlternatively,
sudo usermod --home /home/amdadul/Public --move-home Lisa➌ Now, press the ENTER key.
➍ Type your password.
➎ Tap ENTER again.
➏ Now, type the following command into the command prompt:
getent passwd Lisa➐ Hit ENTER button.
Output >
In the following image, you can see that I have moved the home directory of the user Lisa from /home/Lisa to /home/amdadul/Public.
Example 10: Change User Login Shell With the “usermod” Command in Linux
The usermod command allows you to change the login shell of any user. To change the login shell of any user using the usermod command, you have to use the option -s or –shell. In this section, I will change the login shell of user Lisa, Whose current login shell is /bin/sh shown in the image below.
To perform the same thing follow the steps below.
Steps to Follow >
➊ Open the Ubuntu Terminal.
➋ Type the following command into the command prompt:
sudo usermod -s /bin/bash LisaAlternatively,
sudo usermod --shell /bin/bash Lisa➌ Now, tap the ENTER button.
➍ Type your Password.
➎ Tap ENTER key again.
➏ Now type the following command into the command prompt:
getent passwd Lisa➐ Press ENTER key.
Output >
In the image below, you can see that I have changed Lisa’s login shell from /bin/sh to /bin/bash.
Example 11: Modify User Account Expiry Date With the “usermod” Command in Linux
The usermod command allows you to modify the expiry date of a user account. In this section, I will modify the expiry date of user Lisa whose user details I obtained by running the command below.
sudo chage -l LisaThe result I got by running the command above is shown below.
To modify the expiration date of a user account you can follow the steps below.
Steps to Follow >
➊ Launch the Ubuntu Terminal.
➋ Type the following command into the command prompt:
sudo usermod -e 2023-02-22 LisaAlternatively,
sudo usermod --expiredate 2023-02-22 Lisa➌ Now, tap the ENTER button.
➍ Provie your Password.
➎ Tap ENTER key again.
➏ Now type the following command into the command prompt:
sudo chage -l Lisa➐ Press ENTER key.
Output >
In the following image, you can see that I have modified the expiration date of the user account ‘Lisa’ from having no expiration date to Jan 22, 2023.
Example 12: Update the User Password Using the “usermod” Command in Linux
The usermod command provides modification permission for a user’s password. That means you can set a new password for a user or change the existing password of a user by using the usermod command. In the section below, I will discuss both cases.
Case A: Set Password of a User Without Having One
In this section, I will show you the process of setting a password for user Lisa, who has no password. You can see the current password status in the image below by running the command sudo grep Lisa /etc/shadow.
I am providing the steps to set a new password for Lisa in the section below and you can do the same by following the steps below.
Steps to Follow >
➊ First, open the Ubuntu Terminal.
➋ Execute the following command
sudo usermod -p abcdefg123 LisaAlternatively,
sudo usermod --password abcdefg123 Lisa➌ Now, tap the ENTER button.
➍ Input your Password.
➎ Press ENTER again.
➏ Now type the following command into the command prompt:
sudo grep Lisa /etc/shadow➐ Tap ENTER key.
Output >
You can see in the image that I have set up a password for user Lisa.
Case B: Change the Existing Password of a User
Setting up a new password and changing process of the existing password is almost the same. In this section, I will show you the process of changing a password for user Lisa, whose current password is abcdefg123. You can see the current password status in the image below by running the command sudo grep Lisa /etc/shadow.
I am providing the steps to change an existing password for Lisa in the section below and you can do the same by following the steps below.
Steps to Follow >
➊ Open the Ubuntu Terminal, first.
➋ Run the following command
sudo usermod -p hijklm123 LisaAlternatively,
sudo usermod --password hijklm123 Lisa➌ Now, hit the ENTER button.
➍ Type your Password.
➎ Press ENTER again.
➏ Now type the following command into the command prompt:
sudo grep Lisa /etc/shadow➐ Tap ENTER key.
Output >
You can see in the image that I have changed the existing password abcdefg123 to hijklm123 for user Lisa.
Example 13: Lock User Account Using the “usermod” Command in Linux
The usermod command allows you to lock an account. You can lock an account with the usermod command followed by the option -L or –lock. Now, I will show you the process of locking a user account. You can do the same by following the steps below.
Steps to Follow >
➊ Launch the Ubuntu Terminal.
➋ Execute the following command
sudo usermod -L LisaAlternatively,
sudo usermod --lock Lisa➌ Now, tap the ENTER button.
➍ Input your Password.
➎ Press ENTER again.
➏ Now type the following command into the command prompt:
sudo grep Lisa /etc/shadow➐ Tap ENTER key.
Output >
In the image, the “!” sign after the name of the account Lisa illustrates that this account is locked.
Example 14: Unlock User Account Using the “usermod” Command in Linux
In the previous section, I have shown you the process of locking the account of user Lisa. In this section, I will unlock that account with the usermod command follower by the option -U or –unlock. Now, I will show you the process of unlocking the user account ‘Lisa’. You can do the same by following the steps below.
Steps to Follow >
➊ Open the Ubuntu Terminal.
➋ Run the following command
sudo usermod -U LisaAlternatively,
sudo usermod --unlock Lisa➌ Now, tap the ENTER button.
➍ Provide your Password.
➎ Press ENTER again.
➏ Now type the following command into the command prompt:
sudo grep Lisa /etc/shadow➐ Tap ENTER key.
Output >
In the following image, You can see that there is no “!” sign after the name of the account Lisa which illustrates that this account is being unlocked.
Conclusion
In this article, I’ve discussed the usermod command which is useful to modify user name, user ID, groups, home directory, password, user shell, expiry date, and other user details of an existing user. At the same time, I’ve discussed its options and provided some relevant examples. Undoubtedly, this article will help you better understand the usermod command and its use. Consequently, it will make your journey easier to become a power user of the Linux command line.
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