MKINITRAMFS(8)                          mkinitramfs manual                         MKINITRAMFS(8)



NAME
       mkinitramfs - low-level tool for generating an initramfs image


SYNOPSIS
       mkinitramfs [-c compress] [-d confdir] [-k] -o outfile [-r root] [-v] [version]

       mkinitramfs [--supported-host-version= hversion]

       mkinitramfs [--supported-target-version= tversion]


DESCRIPTION
       The  mkinitramfs  script generates an initramfs image.  The initramfs is a compressed cpio
       archive. The archive can be used on a different box of the same arch with the  correspond‐
       ing  Linux  kernel.   mkinitramfs  is  meant for advanced usage. On your local box update-
       initramfs calls mkinitramfs with the relevant parameters.  update-initramfs keeps  sha1sum
       of  generated  initramfs.  It takes care to generate backups and eventually runs the boot‐
       loader.

       At boot time, the kernel unpacks that archive into RAM disk, mounts and uses it as initial
       root file system. All finding of the root device happens in this early userspace.


OPTIONS
        -c  compress
              Override the COMPRESS setting in initramfs.conf.


        -d  confdir
              Set an alternate configuration directory.


        -k    Keep the temporary directory used to make the image.


        -o  outfile
              Write the image to outfile.


        -r  root
              Override the ROOT setting in initramfs.conf.


        -v    Set the verbose mode output.


        version
              Set the kernel version of the initramfs image (defaults to the running kernel).


       --supported-host-version=hversion
              This  option queries if mkinitramfs can create ramdisks on a running kernel of ver‐
              sion hversion.


       --supported-target-version=tversion
              This option queries if mkinitramfs can create ramdisks for kernel version tversion.


ENVIRONMENT
       mkinitramfs honours the TMPDIR environment variable. If set, it uses subdirectories in the
       given  directory  to  create  its  temporary working directories. Else it uses /var/tmp as
       default value for that purpose. The given directory should be on a filesystem which allows
       the  execution  of  files  stored there, i.e.  should not be mounted with the noexec mount
       option.


FILES
       /etc/initramfs-tools/initramfs.conf
              The default configuration file for the script. See initramfs.conf(5) for a descrip‐
              tion of the available configuration parameter.


       /etc/initramfs-tools/modules
              Specified  modules  will  be  put in the generated image and loaded when the system
              boots. The format - one per line - is identical to that of /etc/modules,  which  is
              described in modules(5).


       /etc/initramfs-tools/conf.d
              The  conf.d  directory  allows one to hardcode bootargs at initramfs build time via
              config snippets. This allows one to set ROOT or RESUME.  This is especially  useful
              for bootloaders, which do not pass an root bootarg.


       /etc/initramfs-tools/DSDT.aml
              If  this  file exists, it will be appended to the initramfs in a way that causes it
              to be loaded by ACPI.


EXAMPLES
       Create an initramfs for current running kernel:


       mkinitramfs -o ~/tmp/initramfs-$(uname -r)

       Create an initramfs for specific kernel and keep builddirs:


       mkinitramfs -k -o ~/tmp/initramfs-2.6.21-686 2.6.21-686

       Debug initramfs creation (check out written logfile)

       sh -x mkinitramfs -o ~/tmp/initramfs-$(uname -r) 2> ~/tmp/log


AUTHOR
       The initramfs-tools are written by Maximilian Attems <maks AT debian.org>, Jeff Bailey <jbai‐
       ley AT raspberryginger.com> and numerous others.


SEE ALSO
        initramfs.conf(5), initramfs-tools(8), update-initramfs(8), lsinitramfs(8).



Linux                                       2010/04/07                             MKINITRAMFS(8)