///// vim:set ts=4 sw=4 syntax=asciidoc noet: ///// mkinitcpio(8) ============= Name ---- mkinitcpio - Create an initial ramdisk environment Synopsis -------- 'mkinitcpio' [options] Description ----------- Creates an initial ramdisk environment for booting the linux kernel. The initial ramdisk is in essence a very small environment (early userspace) which loads various kernel modules and sets up necessary things before handing over control to init. This makes it possible to have, for example, encrypted root filesystems and root filesystems on a software RAID array. mkinitcpio allows for easy extension with custom hooks, has autodetection at runtime, and many other features. Options ------- *-A, \--add* 'hooks':: Add the additional 'hooks' to the image. These will be processed in order after all other hooks from the config file. Multiple hooks should be comma-separated. This option can be specified multiple times. *-c, \--config* 'config':: Use 'config' file to generate the ramdisk. Default: /etc/mkinitcpio.conf *-g, \--generate* 'filename':: Generate a CPIO image as 'filename'. Default: no; this means nothing will be written to the filesystem unless this option is specified. *-H, \--hookhelp* 'hookname':: Output help for hookname 'hookname'. *-h, \--help*:: Output a short overview of available command-line switches. *-k, \--kernel* 'kernelversion':: Use 'kernelversion', instead of the current running kernel. This may be a path to a kernel image or a specific kernel version. *-L, \--listhooks*:: List all available hooks. *-M, \--automods*:: Display modules found via autodetection. mkinitcpio will automatically try to determine which kernel modules are needed to start your computer. This option lists which modules were detected. *-n, \--nocolor*:: Disable color output. *-p, \--preset* 'preset':: Build initramfs image(s) according to specified 'preset'. This may be a file in /etc/mkinitcpio.d (without the .preset extension) or a full, absolute path to a file. *-S, \--skiphooks* 'hooks':: Skip 'hooks' when generating the image. Multiple hooks should be comma-separated. This option can be specified multiple times. *-s, \--save*:: Saves the build directory for the initial ramdisk. Default: no; This means the directory will not be retained if this option isn't specified. Useful for debugging purposes. *-t, \--builddir* 'tmpdir':: Use 'tmpdir' as the temporary build directory instead of /tmp. 'tmpdir' must exist. The 'TMPDIR' environment variable is also honored to set this location, but the command line option will take precedence. *-v, \--verbose*:: Verbose output. Outputs more information about what's happening during creation of the ramdisk. *-z, \--compress* 'compress':: Override the compression method with the 'compress' program. About Hooks ----------- A hook is a script that executes in the initial ramdisk. Scripts are listed in order of execution as a space separated string in the *HOOKS* variable in the mkinitcpio configuration file. Hooks can, for example, set up the udev device filesystem, load IDE modules, etc. About Presets ------------- A preset is a pre-defined definition on how to create an initial ramdisk. Instead of specifying the configuration file and which output file, every time you generate a new initial ramdisk, you define a preset and use the -p switch to generate an initial ramdisk according to your preset. Presets are located in /etc/mkinitcpio.d Early Init Environment ---------------------- mkinitcpio gives special treatment to certain environment variables passed on the kernel command line: *break*['=']:: If specified, mkinitcpio will start a shell during early init. The optional parameter controls when this occurs: when 'premount' or no parameter are specified, the shell will be launched prior to mounting root. If 'postmount' is specified, the shell will be launched after mounting root. *disablehooks=*'hooklist':: This is a comma separated list of hooks which will be skipped during early init. *earlymodules=*'modulelist':: This is a comma separated list of modules which will be loaded prior to any others. This is generally not needed, and usually points to a configuration or kernel problem. *quiet*:: Causes mkinitcpio to output fewer messages during boot. Errors will not be suppressed. *ro*:: Specifies that root should be mounted with readonly permissions. This is the default behavior. *rw*:: Specifies that root should be mounted with readwrite permissions. This is generally only useful if your initramfs uses the 'fsck' hook. *root=*'rootdevice':: This variable describes the root partition which early init will mount before passing control to the real init. mkinitcpio understands a variety of formats, the most basic of which is the path to the block device, either directly, such as '/dev/sda2', or using a udev symlink such as '/dev/disk/by-label/CorsairF80-root'. Support for identification by LABEL or UUID tags are also supported, such as, 'LABEL=CorsairF80-root'. As of util-linux 2.22, PARTUUID is also supported. Identification via hex encoded major/minor device ID is supported for legacy reasons, but should not be used. *rootdelay=*'seconds':: Sets the delay, in seconds, that mkinitcpio is willing to wait for the root device to show up, if it is not available immediately. This defaults to 5 seconds. If an invalid integer is passed, this variable will have no effect. These are only the variables that the core of mkinitcpio honor. Additional hooks may look for other environment variables and should be documented by the help output for the hook. Files ----- '/etc/mkinitcpio.conf':: Default configuration file for mkinitcpio. '/etc/mkinitcpio.d':: Folder containing mkinitcpio presets. '/usr/lib/initcpio':: '/lib/initcpio':: Files related to creating an initial ramdisk. Examples -------- *mkinitcpio*:: Perform a 'dry-run'. This will generate an initial ramdisk but will not write anything. Use -g to create the real image. *mkinitcpio -p linux*:: Create an initial ramdisk based on the 'linux' preset. *mkinitcpio -g /boot/initramfs-linux.img -k /boot/vmlinuz-linux*:: Create an initial ramdisk for the kernel at /boot/vmlinuz-linux. The resulting image will be written to /boot/initramfs-linux.img. See also -------- A more thorough article on configuring mkinitcpio: *initrd*(4), *lsinitcpio*(1) Bugs ---- Upon writing this manpage, there were no noticeable bugs present. Please visit for an up to date list. Authors ------- mkinitcpio is created by the Arch Linux Developer community. Manpage written by::: * Glenn 'RedShift' Matthys Manpage contributions by::: * Jens 'byte' Adam * Geir 'gejr' Vaagland * Joerie 'Thralas' de Gram Copyright --------- Copyright (c) Arch Linux