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.

       -l  compresslevel
              Override the COMPRESSLEVEL setting in initramfs.conf.

       -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 execution 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 reproducible 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 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(7),    update-initramfs(8),    lsinitramfs(8),
       unmkinitramfs(8).