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
       corresponding  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
       bootloader.

       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
              version 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 /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
              description 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@debian.org>, Jeff Bailey
       <jbailey@raspberryginger.com> and numerous others.

SEE ALSO

        initramfs.conf(5), initramfs-tools(8), update-initramfs(8).