You may have to remove users account at after sometime when a user account may become dormant for so long, or the user may leave the organization or company or any other reasons.
When removing user accounts on a Linux system, it is also important to remove their home directory to free up space on the storage devices for new system users or other services.
Deleting/Removing a User Account with His/Her Home Directory
1. For demonstration purpose, first I will start by creating two user accounts on my system that is user rootadminz and user adminlinux with their home directories /home/rootadminz and /home/adminlinux respectively using adduser command.
# adduser rootadminz # passwd rootadminz # adduser adminlinux # passwd adminlinux
From the screenshot above, I have used the adduser command to create user accounts on Linux. You can also use useradd command, both are same and does the same job.
2. Let’s now move further to see how to delete or remove user accounts in Linux using deluser (For Debian and it’s derivatives) and userdel (For RedHat/CentOS based systems) command.
The directives inside the configuration file for deluser and userdel commands determine how this it will handle all user files and directory when you run the command.
Let us look at the configuration file for the deluser command which is /etc/deluser.conf on Debian derivatives such as Ubuntu, Kali, Mint and for RHEL/CentOS/Fedora users, you can view the /etc/login.defs files.
The values in the these configuration are default and can be changed as per your needs.
# vi /etc/deluser.conf [On Debian and its derivatives] # vi /etc/login.defs [On RedHat/CentOS based systems]
3. To delete a user with home directory, you can use the advanced way by following these steps on your Linux server machine. When users are logged on to the server, they use services and run different processes. It is important to note that the user can only be deleted effectively when they are not logged on to the server.
Lock User Accounts in Linux
Start by locking the user account password so that there is no access for the user to the system. This will prevent a user from running processes on the system.
The passwd command including the –lock option can help you achieve this:
# passwd --lock rootadminz Locking password for user rootadminz. passwd: Success
Find and Kill All Running Processes of User
Next, find out all running processes of user account and kill them by determining the PIDs (Process IDs) of processes owned by the user using:
# pgrep -u rootadminz 1947 1959 2091 2094 2095 2168 2175 2179 2183 2188 2190 2202 2207 2212 2214
Then you can list the processes in terms of username, PIDs, PPIDs (Parent Process IDs), the terminal used, process state, command path in a full formatting style with the help of the following command as shown:
# ps -f --pid $(pgrep -u rootadminz) UID PID PPID C STIME TTY STAT TIME CMD
rootadminz 1947 1 0 10:49 ? SLl 0:00 /usr/bin/gnome-keyring-daemon --daemonize --login rootadminz 1959 1280 0 10:49 ? Ssl 0:00 mate-session rootadminz 2091 1959 0 10:49 ? Ss 0:00 /usr/bin/ssh-agent /usr/bin/dbus-launch --exit-with-session /usr/bin/im-launch mate-session rootadminz 2094 1 0 10:49 ? S 0:00 /usr/bin/dbus-launch --exit-with-session /usr/bin/im-launch mate-session rootadminz 2095 1 0 10:49 ? Ss 0:00 //bin/dbus-daemon --fork --print-pid 6 --print-address 9 --session rootadminz 2168 1 0 10:49 ? Sl 0:00 /usr/lib/dconf/dconf-service rootadminz 2175 1959 0 10:49 ? Sl 0:02 /usr/bin/mate-settings-daemon rootadminz 2179 1959 0 10:49 ? Sl 0:47 marco rootadminz 2183 1 0 10:49 ? Sl 0:00 /usr/lib/gvfs/gvfsd rootadminz 2188 1959 0 10:49 ? Sl 0:00 mate-panel rootadminz 2190 1 0 10:49 ? Sl 0:00 /usr/lib/gvfs/gvfsd-fuse /run/user/1000/gvfs -f -o big_writes rootadminz 2202 1 0 10:49 ? S
Once you find all the running processes of user, you can use the killall command to kill those running processes as shown.
# killall -9 -u rootadminz
The -9 is the signal number for the SIGKILL signal or use -KILL instead of -9 and -u defines username.
Note: In recent releases of RedHat/CentOS 7.x versions and Fedora 21+, you will get error message as:
-bash: killall: command not found
To fix such error, you need to install psmisc package as shown:
# yum install psmisc [On RedHat/CentOS 7.x] # dnf install psmisc [On Fedora 21+ versions]
Backup User Data Before Deleting
Next you can backup users files, this can be optional but it is recommended for future use when need arises to review user account details and files.
I have used the tar utilities to create a backup of users home directory as follows:
# tar jcvf /user-backups/rootadminz-home-directory-backup.tar.bz2 /home/rootadminz
Delete/Remove User Account and Files
Now you can safely remove user together with his/her home directory, to remove all user files on the system use the --remove-all-files option in the command below:
# deluser --remove-home rootadminz [On Debian and its derivatives] # userdel --remove rootadminz [On RedHat/CentOS based systems]
