mkinitramfs

MKINITRAMFS(8)               System Administration              MKINITRAMFS(8)

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

SYNOPSIS
       mkinitramfs [option]...  -o outfile [version]
       mkinitramfs -h

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).

       -h, --help
              Display usage information and exit.

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 execu-
       tion of files stored there, i.e.  should not be mounted with the noexec
       mount option.

       If  SOURCE_DATE_EPOCH is set, mkinitramfs attempts to generate a repro-
       ducible initramfs image.

FILES
       /etc/initramfs-tools/initramfs.conf
              The   default   configuration   file   for   the   script.   See
              initramfs.conf(5)  for a description of the available configura-
              tion 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(7),    update-initramfs(8),
       lsinitramfs(8), unmkinitramfs(8).

initramfs-tools                   2018/07/18                    MKINITRAMFS(8)