rmmod Command: Tutorial & Examples
Removing Linux Kernel Modules
rmmod command is used to remove a module from the Linux Kernel. A module is a piece of
code that can be added or removed from the kernel on-the-fly without rebooting the system.
Removing unnecessary modules can help in freeing up the system resources and keeping the kernel lean and efficient. This is particularly useful in a server environment where performance and resource utilization are of paramount importance.
rmmod works by taking the name of the module as an argument and removing it from the kernel. However, it can only
remove a module if it's not being used, or if no other modules depend on it.
rmmod command is a critical tool in the arsenal of a Linux server administrator. It can help in troubleshooting
issues related to kernel modules, and it gives the administrator fine control over the modules loaded in the kernel.
Here are some examples of how to use the
To remove a module named
modulename, you would use:
sudo rmmod modulename
Note that you need to have root privileges to use
If you are unsure whether a module is in use or not, you can use the
lsmodcommand to see the status of all loaded modules. Here's how you do it:
This will give you output like below:
Module Size Used by modulename 16384 0 ...
The 'Used by' column shows how many times the module is being used. If it is '0', you can safely remove the module.
To remove a module and all its dependent modules, you can use the
modprobecommand with the
sudo modprobe -r modulename
This will remove the module
modulenameand all modules that depend on it.
Common difficulties with
rmmod is a powerful tool, it should be used with caution. Removing a critical module can render the system
unstable or even unusable. Always make sure you understand what a module does before removing it.
Another common issue is that
rmmod can only remove a module if it's not being used, and if no other modules depend on
it. If you try to remove a module which is in use or has dependents,
rmmod would fail with an error message.
rmmod and other such commands give you a lot of power over your system, but with great power comes great
responsibility. Always exercise caution when dealing with kernel modules and always have a backup of your data.