How do I change user name (rename user name) or UID under a Linux operating system using command line tools? How do I change or rename username in Linux?
You need to use the usermod command to change user name under a Linux operating systems. This command modifies the system account files to reflect the changes that are specified on the command line. Do not edit /etc/passwd file by hand or using a text editor such as vi. This page explains how to change or rename username in Linux using the usermod command.
Linux Change or Rename User Command Syntax
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:
daemon bin sys sync games man lp mail news uucp proxy www-data backup .... .. .... vivek raj marlena tristan wendy rob systemd-coredump dnsmasq kernoops rtkit whoopsie usbmux cups-pk-helper nm-openvpn speech-dispatcher saned colord hplip geoclue pulse gnome-initial-setup gdm tcpdump nvidia-persistenced tss nm-openconnect vnstat lxd postfix
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 filegrep '^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
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:
# usermod -l jerry tom
usermod: user tom is currently used by process 6886
You need to kill all Linux process owned by user named tom and forcefully logged them out of the system:
# pkill -u tom pid # pkill -9 -u tom # usermod -l jerry tom
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
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:
uid=1001(jerry) gid=1001(jerry) groups=1001(jerry) drwxr-xr-x 2 jerry jerry 4096 Apr 21 15:53 /home/jerry/
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.
