Linux Commands Examples

A great documentation place for Linux commands


Add and remove modules from the Linux Kernel

see also : insmod - rmmod - lsmod - modinfo


modprobe [-v] [-V] [-C config-file] [-n] [-i] [-q] [-b] [modulename] [module parameters...]

modprobe [-r] [-v] [-n] [-i] [modulename...]

modprobe [-c]

modprobe [--dump-modversions] [filename]

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sudo modprobe -r iwlagn
sudo modprobe iwlagn
modprobe dm_mod

Understanding modprobe.conf

man modprobe.conf

If that doesn't tell you what you need to know, can you ask a more specific question?


Is there a way to refresh the current configuration used by modprobe with a newly updated modules.conf file?

If you're just testing modules out, you should be able to use modprobe <module> and modprobe -r <module> to insert and remove modules from the linux kernel, respectively. insmod and rmmod should also perform the same functions (inserting and removing).


It sounds like you're looking for the mapping directive in /etc/networking/interfaces. See man interfaces for details on how to alias networking devices. Note that terminology-wise, an "alias" is a second, third, or otherwise additional IP for an IP device, resulting in an interface with multiple IPs. A "mapping" is used to map logical interface names (ifconfig LOGICAL_INTERFACE up) to real interface names.


modprobe -k -q (missing parameter)

The -k flag in older modprobe versions was used to set the autoclean flag on loaded modules. The autoclean flag was part of a mechanism in the kernel that allowed loaded modules that had not been used for a while to be unloaded automatically. If you listed loaded kernel modules on such a system, you could easily tell which modules were loaded with the autoclean bit set by looking for the (autoclean) tag somewhere on the line for the listed module.

The -k flag is missing from recent modprobe versions. I cannot say with certainty whether the use of this feature has been depreciated in recent kernel.

You could look at the manpage for an older version of modprobe here. And this, and this mention the autoclean flag.


To control decibels in speakers by Ubuntu

Normally in Gnome you use the Volume Applet to adjust the volume. Right-click the top panel and click "Add to Panel...". Scroll down until you see "Volume Control" and press the Add button. Now there is a speaker in the top panel that can be used to control the volume and show the current volume.

alt text


What does `modprobe option` do?

You are absolutely right, modprobe option does attempt to load the module option, controlled by the kernel config parameter USB_SERIAL_OPTION.

Some more informations are found in the kernel sources (drivers/usb/serial/Kconfig)

        tristate "USB driver for GSM and CDMA modems"
          This driver also supports several PCMCIA cards which have a
        built-in OHCI-USB adapter and an internally-connected GSM modem.
        The USB bus on these cards is not accessible externally.
          Supported devices include (some of?) those made by:
        Option, Huawei, Audiovox, Novatel Wireless, or Anydata.
          If this driver doesn't recognize your device,
        it might be accessible via the FTDI_SIO driver.

How to track this down:

  1. Check, if you have such a kernel module (this is only working, if it's enabled in your kernel config)

    $ find /lib/modules -name option.ko
  2. Alternatively, you can try if the module loads

    # modprobe option
    # lsmod | grep option
    option                 33128  0 
    usb_wwan               13044  1 option
    usbserial              23912  2 option,usb_wwan
  3. Now, you can try to find the source files (this only works if the module is included in your current kernel sources)

    $ find /usr/src/linux -name option.c

    You mentioned, the module has something todo with a USB modem, so the second match sounds promising.

  4. You can also find the kernel config parameter

    $ find /usr/src/linux -name Makefile -exec grep -H option\.o '{}' \;
    /usr/src/linux/drivers/gpu/drm/nouveau/Makefile:nouveau-y += core/core/option.o
    /usr/src/linux/drivers/usb/serial/Makefile:obj-$(CONFIG_USB_SERIAL_OPTION)                   += option.o

    Now, you can have a look at /usr/src/linux/drivers/usb/serial/Kconfig and find the description I quoted at the beginning.

  5. Finally, have a look at the source itself (.../drivers/usb/serial/option.c), and voilĂ  you find among other things the author's explanation of the name

    This driver exists because the "normal" serial driver doesn't work too well with GSM modems. Issues:

    • data loss -- one single Receive URB is not nearly enough
    • nonstandard flow (Option devices) control
    • controlling the baud rate doesn't make sense

      This driver is named "option" because the most common device it's
      used for is a PC-Card (with an internal OHCI-USB interface, behind
      which the GSM interface sits), made by Option Inc.

      Some of the "one port" devices actually exhibit multiple USB instances on the USB bus. This is not a bug, these ports are used for different device features.


Installing Arch Linux, issue with `modprobe efivars`

There is a bit of a glitch in the tutorial for installing Archlinux on UEFI systems, but you can get past this particular hang issue like this:

You probably tried to run that modprobe command from inside the chroot of your target system. That won't get you anywhere, you need the functionality loaded in the host system's kernel. In fact my experience with the 2013.11 install media is that you don't need to load the module at all, it is already loaded. The problem is that the sysfs directories it uses are not accessible from inside the chroot, so that's the problem you need to fix.

  1. Leave your terminal open to the chroot, but switch to a new console (Alt+F2)

  2. Check that the /sys/firmware/efi/efivars directory exists. If it does not, then modprobe efivars, but I suspect you will find it does.

  3. Bind mount the directory into your choot (adjust if you are not using /mnt)

    mount --bind /sys/firmware/efi/efivars /mnt/sys/firmware/efi/efivars
  4. Switch back to your first terminal (Alt+F1) and try your next command again. Depending on where you are in the install process, your next move is probably something like this: (assumes you have the FAT32 formatted BIOS partition mounted on /boot/efi inside the chroot)

    grub-install --target=x86_64-efi --efi-directory=/boot/efi --bootloader-id=grub --recheck
    grub-mkconfig -o /boot/grub/grub.cfg

If for some reason you run into problems in step #3 such as the directory you are mounting to not existing, then you haven't properly followed step #1. It is important to use the arch-chroot command to initialize the target system file space and only then use anther console to run the bind mount. The reason is that the arch-chroot script sets of several other bind mounts including ones for /proc and /sys that must be in place before you you can add in the one that is missing for efi-vars. The above instructions have you opening a second console to do this specifically so you don't loose those other bind mounts while you add this one.


modprobe intelligently adds or removes a module from the Linux kernel: note that for convenience, there is no difference between _ and - in module names (automatic underscore conversion is performed). modprobe looks in the module directory /lib/modules/’uname -r’ for all the modules and other files, except for the optional configuration files in the /etc/modprobe.d directory (see modprobe.d(5)). modprobe will also use module options specified on the kernel command line in the form of <module>.<option> and blacklists in the form of modprobe.blacklist=<module>.

Note that unlike in 2.4 series Linux kernels (which are not supported by this tool) this version of modprobe does not do anything to the module itself: the work of resolving symbols and understanding parameters is done inside the kernel. So module failure is sometimes accompanied by a kernel message: see dmesg(8).

modprobe expects an up-to-date modules.dep.bin file (or fallback human readable modules.dep file), as generated by the corresponding depmod utility shipped along with modprobe (see depmod(8)). This file lists what other modules each module needs (if any), and modprobe uses this to add or remove these dependencies automatically.

If any arguments are given after the modulename, they are passed to the kernel (in addition to any options listed in the configuration file).


-a --all

Insert all module names on the command line.

-b --use-blacklist

This option causes modprobe to apply the blacklist commands in the configuration files (if any) to module names as well. It is usually used by udev(7).

-C --config

This option overrides the default configuration directory (/etc/modprobe.d).

This option is passed through install or remove commands to other modprobe commands in the MODPROBE_OPTIONS environment variable.

-c --showconfig

Dump out the effective configuration from the config directory and exit.


Print out a list of module versioning information required by a module. This option is commonly used by distributions in order to package up a Linux kernel module using module versioning deps.

-d --dirname

Directory where modules can be found, /lib/modules/RELEASE by default.


Normally, modprobe will succeed (and do nothing) if told to insert a module which is already present or to remove a module which isn't present. This is ideal for simple scripts; however, more complicated scripts often want to know whether modprobe really did something: this option makes modprobe fail in the case that it actually didn't do anything.


Every module contains a small string containing important information, such as the kernel and compiler versions. If a module fails to load and the kernel complains that the "version magic" doesn't match, you can use this option to remove it. Naturally, this check is there for your protection, so this using option is dangerous unless you know what you're doing.

This applies to any modules inserted: both the module (or alias) on the command line and any modules on which it depends.


When modules are compiled with CONFIG_MODVERSIONS set, a section detailing the versions of every interfaced used by (or supplied by) the module is created. If a module fails to load and the kernel complains that the module disagrees about a version of some interface, you can use "--force-modversion" to remove the version information altogether. Naturally, this check is there for your protection, so using this option is dangerous unless you know what you're doing.

This applies any modules inserted: both the module (or alias) on the command line and any modules on which it depends.

-f --force

Try to strip any versioning information from the module which might otherwise stop it from loading: this is the same as using both --force-vermagic and --force-modversion. Naturally, these checks are there for your protection, so using this option is dangerous unless you know what you are doing.

This applies to any modules inserted: both the module (or alias) on the command line and any modules it on which it depends.

-i --ignore-install --ignore-remove

This option causes modprobe to ignore install and remove commands in the configuration file (if any) for the module specified on the command line (any dependent modules are still subject to commands set for them in the configuration file). Both install and remove commands will currently be ignored when this option is used regardless of whether the request was more specifically made with only one or other (and not both) of --ignore-install or --ignore-remove. See modprobe.d(5).

-n --dry-run --show

This option does everything but actually insert or delete the modules (or run the install or remove commands). Combined with -v, it is useful for debugging problems. For historical reasons both --dry-run and --show actually mean the same thing and are interchangeable.

-q --quiet

With this flag, modprobe won't print an error message if you try to remove or insert a module it can't find (and isn't an alias or install/remove command). However, it will still return with a non-zero exit status. The kernel uses this to opportunistically probe for modules which might exist using request_module.

-R --resolve-alias

Print all module names matching an alias. This can be useful for debugging module alias problems.

-r --remove

This option causes modprobe to remove rather than insert a module. If the modules it depends on are also unused, modprobe will try to remove them too. Unlike insertion, more than one module can be specified on the command line (it does not make sense to specify module parameters when removing modules).

There is usually no reason to remove modules, but some buggy modules require it. Your distribution kernel may not have been built to support removal of modules at all.

-S --set-version

Set the kernel version, rather than using uname(2) to decide on the kernel version (which dictates where to find the modules).


List the dependencies of a module (or alias), including the module itself. This produces a (possibly empty) set of module filenames, one per line, each starting with "insmod" and is typically used by distributions to determine which modules to include when generating initrd/initramfs images. Install commands which apply are shown prefixed by "install". It does not run any of the install commands. Note that modinfo(8) can be used to extract dependencies of a module from the module itself, but knows nothing of aliases or install commands.

-s --syslog

This option causes any error messages to go through the syslog mechanism (as LOG_DAEMON with level LOG_NOTICE) rather than to standard error. This is also automatically enabled when stderr is unavailable.

This option is passed through install or remove commands to other modprobe commands in the MODPROBE_OPTIONS environment variable.

-V --version

Show version of program and exit.

-v --verbose

Print messages about what the program is doing. Usually modprobe only prints messages if something goes wrong.

This option is passed through install or remove commands to other modprobe commands in the MODPROBE_OPTIONS environment variable.


This manual page originally Copyright 2002, Rusty Russell, IBM Corporation. Maintained by Jon Masters and others.


The MODPROBE_OPTIONS environment variable can also be used to pass arguments to modprobe.

see also

modprobe.d, insmod , rmmod , lsmod , modinfo


Jon Masters <jcm[:at:]jonmasters[:dot:]org>


Robby Workman <rworkman[:at:]slackware[:dot:]com>


Lucas De Marchi <lucas.demarchi[:at:]profusion[:dot:]mobi>


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